Aggregations: Renaming reducers to Pipeline Aggregators

docs/reference/aggregations.asciidoc

@@ -23,7 +23,7 @@ it is often easier to break them into two main families:
 <<search-aggregations-metrics, _Metric_>>::
 				Aggregations that keep track and compute metrics over a set of documents.
 
-<<search-aggregations-reducer, _Reducer_>>::
+<<search-aggregations-pipeline, _Pipeline_>>::
 				Aggregations that aggregate the output of other aggregations and their associated metrics
 
 The interesting part comes next. Since each bucket effectively defines a document set (all documents belonging to
@@ -100,6 +100,6 @@ include::aggregations/metrics.asciidoc[]
 
 include::aggregations/bucket.asciidoc[]
 
-include::aggregations/reducer.asciidoc[]
+include::aggregations/pipeline.asciidoc[]
 
 include::aggregations/misc.asciidoc[]

docs/reference/aggregations/pipeline.asciidoc

@@ -1,39 +1,39 @@
-[[search-aggregations-reducer]]
+[[search-aggregations-pipeline]]
 
-== Reducer Aggregations
+== Pipeline Aggregations
 
 coming[2.0.0]
 
 experimental[]
 
-Reducer aggregations work on the outputs produced from other aggregations rather than from document sets, adding
+Pipeline aggregations work on the outputs produced from other aggregations rather than from document sets, adding
-information to the output tree. There are many different types of reducer, each computing different information from
+information to the output tree. There are many different types of pipeline aggregation, each computing different information from
 other aggregations, but these types can broken down into two families:
 
 _Parent_::
-                A family of reducer aggregations that is provided with the output of its parent aggregation and is able
+                A family of pipeline aggregations that is provided with the output of its parent aggregation and is able
                 to compute new buckets or new aggregations to add to existing buckets.
 
 _Sibling_::
-                Reducer aggregations that are provided with the output of a sibling aggregation and are able to compute a
+                Pipeline aggregations that are provided with the output of a sibling aggregation and are able to compute a
                 new aggregation which will be at the same level as the sibling aggregation.
 
-Reducer aggregations can reference the aggregations they need to perform their computation by using the `buckets_paths`
+Pipeline aggregations can reference the aggregations they need to perform their computation by using the `buckets_paths`
 parameter to indicate the paths to the required metrics. The syntax for defining these paths can be found in the
 <<bucket-path-syntax, `buckets_path` Syntax>> section below.
 
-Reducer aggregations cannot have sub-aggregations but depending on the type it can reference another reducer in the `buckets_path`
+Pipeline aggregations cannot have sub-aggregations but depending on the type it can reference another pipeline in the `buckets_path`
-allowing reducers to be chained.  For example, you can chain together two derivatives to calculate the second derivative
+allowing pipeline aggregations to be chained.  For example, you can chain together two derivatives to calculate the second derivative
 (e.g. a derivative of a derivative).
 
-NOTE: Because reducer aggregations only add to the output, when chaining reducer aggregations the output of each reducer will be
+NOTE: Because pipeline aggregations only add to the output, when chaining pipeline aggregations the output of each pipeline aggregation 
-included in the final output.
+will be included in the final output.
 
 [[bucket-path-syntax]]
 [float]
 === `buckets_path` Syntax
 
-Most reducers require another aggregation as their input.  The input aggregation is defined via the `buckets_path`
+Most pipeline aggregations require another aggregation as their input.  The input aggregation is defined via the `buckets_path`
 parameter, which follows a specific format:
 
 --------------------------------------------------
@@ -47,7 +47,7 @@ PATH                :=  <AGG_NAME>[<AGG_SEPARATOR><AGG_NAME>]*[<METRIC_SEPARATOR
 For example, the path `"my_bucket>my_stats.avg"` will path to the `avg` value in the `"my_stats"` metric, which is
 contained in the `"my_bucket"` bucket aggregation.
 
-Paths are relative from the position of the reducer; they are not absolute paths, and the path cannot go back "up" the
+Paths are relative from the position of the pipeline aggregation; they are not absolute paths, and the path cannot go back "up" the
 aggregation tree. For example, this moving average is embedded inside a date_histogram and refers to a "sibling"
 metric `"the_sum"`:
 
@@ -73,7 +73,7 @@ metric `"the_sum"`:
 <1> The metric is called `"the_sum"`
 <2> The `buckets_path` refers to the metric via a relative path `"the_sum"`
 
-`buckets_path` is also used for Sibling reducer aggregations, where the aggregation is "next" to a series of buckets
+`buckets_path` is also used for Sibling pipeline aggregations, where the aggregation is "next" to a series of buckets
 instead of embedded "inside" them.  For example, the `max_bucket` aggregation uses the `buckets_path` to specify
 a metric embedded inside a sibling aggregation:
 
@@ -109,7 +109,7 @@ a metric embedded inside a sibling aggregation:
 ==== Special Paths
 
 Instead of pathing to a metric, `buckets_path` can use a special `"_count"` path.  This instructs
-the reducer to use the document count as it's input.  For example, a moving average can be calculated on the document
+the pipeline aggregation to use the document count as it's input.  For example, a moving average can be calculated on the document
 count of each bucket, instead of a specific metric:
 
 [source,js]
@@ -141,7 +141,7 @@ There are a couple of reasons why the data output by the enclosing histogram may
 on the enclosing histogram or with a query matching only a small number of documents)
 
 Where there is no data available in a bucket for a given metric it presents a problem for calculating the derivative value for both
-the current bucket and the next bucket. In the derivative reducer aggregation has a `gap policy` parameter to define what the behavior
+the current bucket and the next bucket. In the derivative pipeline aggregation has a `gap policy` parameter to define what the behavior
 should be when a gap in the data is found. There are currently two options for controlling the gap policy:
 
 _skip_::
@@ -154,9 +154,9 @@ _insert_zeros_::
 
 
 
-include::reducer/avg-bucket-aggregation.asciidoc[]
+include::pipeline/avg-bucket-aggregation.asciidoc[]
-include::reducer/derivative-aggregation.asciidoc[]
+include::pipeline/derivative-aggregation.asciidoc[]
-include::reducer/max-bucket-aggregation.asciidoc[]
+include::pipeline/max-bucket-aggregation.asciidoc[]
-include::reducer/min-bucket-aggregation.asciidoc[]
+include::pipeline/min-bucket-aggregation.asciidoc[]
-include::reducer/sum-bucket-aggregation.asciidoc[]
+include::pipeline/sum-bucket-aggregation.asciidoc[]
-include::reducer/movavg-aggregation.asciidoc[]
+include::pipeline/movavg-aggregation.asciidoc[]

docs/reference/aggregations/pipeline/avg-bucket-aggregation.asciidoc

@@ -1,7 +1,7 @@
-[[search-aggregations-reducer-avg-bucket-aggregation]]
+[[search-aggregations-pipeline-avg-bucket-aggregation]]
 === Avg Bucket Aggregation
 
-A sibling reducer aggregation which calculates the (mean) average value of a specified metric in a sibling aggregation. 
+A sibling pipeline aggregation which calculates the (mean) average value of a specified metric in a sibling aggregation. 
 The specified metric must be numeric and the sibling aggregation must be a multi-bucket aggregation.
 
 ==== Syntax

docs/reference/aggregations/pipeline/derivative-aggregation.asciidoc

@@ -1,7 +1,7 @@
-[[search-aggregations-reducer-derivative-aggregation]]
+[[search-aggregations-pipeline-derivative-aggregation]]
 === Derivative Aggregation
 
-A parent reducer aggregation which calculates the derivative of a specified metric in a parent histogram (or date_histogram) 
+A parent pipeline aggregation which calculates the derivative of a specified metric in a parent histogram (or date_histogram) 
 aggregation. The specified metric must be numeric and the enclosing histogram must have `min_doc_count` set to `0` (default
 for `histogram` aggregations).
 
@@ -112,8 +112,8 @@ would be $/month assuming the `price` field has units of $.
 
 ==== Second Order Derivative
 
-A second order derivative can be calculated by chaining the derivative reducer aggregation onto the result of another derivative 
+A second order derivative can be calculated by chaining the derivative pipeline aggregation onto the result of another derivative 
-reducer aggregation as in the following example which will calculate both the first and the second order derivative of the total 
+pipeline aggregation as in the following example which will calculate both the first and the second order derivative of the total 
 monthly sales:
 
 [source,js]

docs/reference/aggregations/pipeline/max-bucket-aggregation.asciidoc

@@ -1,7 +1,7 @@
-[[search-aggregations-reducer-max-bucket-aggregation]]
+[[search-aggregations-pipeline-max-bucket-aggregation]]
 === Max Bucket Aggregation
 
-A sibling reducer aggregation which identifies the bucket(s) with the maximum value of a specified metric in a sibling aggregation
+A sibling pipeline aggregation which identifies the bucket(s) with the maximum value of a specified metric in a sibling aggregation
 and outputs both the value and the key(s) of the bucket(s). The specified metric must be numeric and the sibling aggregation must 
 be a multi-bucket aggregation.
 

docs/reference/aggregations/pipeline/min-bucket-aggregation.asciidoc

@@ -1,7 +1,7 @@
-[[search-aggregations-reducer-min-bucket-aggregation]]
+[[search-aggregations-pipeline-min-bucket-aggregation]]
 === Min Bucket Aggregation
 
-A sibling reducer aggregation which identifies the bucket(s) with the minimum value of a specified metric in a sibling aggregation 
+A sibling pipeline aggregation which identifies the bucket(s) with the minimum value of a specified metric in a sibling aggregation 
 and outputs both the value and the key(s) of the bucket(s). The specified metric must be numeric and the sibling aggregation must 
 be a multi-bucket aggregation.
 

docs/reference/aggregations/pipeline/movavg-aggregation.asciidoc

@@ -1,4 +1,4 @@
-[[search-aggregations-reducers-movavg-reducer]]
+[[search-aggregations-pipeline-movavg-aggregation]]
 === Moving Average Aggregation
 
 Given an ordered series of data, the Moving Average aggregation will slide a window across the data and emit the average
@@ -109,14 +109,14 @@ track the data and only smooth out small scale fluctuations:
 
 [[movavg_10window]]
 .Moving average with window of size 10
-image::images/reducers_movavg/movavg_10window.png[]
+image::images/pipeline_movavg/movavg_10window.png[]
 
 In contrast, a `simple` moving average with larger window (`"window": 100`) will smooth out all higher-frequency fluctuations,
 leaving only low-frequency, long term trends.  It also tends to "lag" behind the actual data by a substantial amount:
 
 [[movavg_100window]]
 .Moving average with window of size 100
-image::images/reducers_movavg/movavg_100window.png[]
+image::images/pipeline_movavg/movavg_100window.png[]
 
 
 ==== Linear
@@ -143,7 +143,7 @@ will closely track the data and only smooth out small scale fluctuations:
 
 [[linear_10window]]
 .Linear moving average with window of size 10
-image::images/reducers_movavg/linear_10window.png[]
+image::images/pipeline_movavg/linear_10window.png[]
 
 In contrast, a `linear` moving average with larger window (`"window": 100`) will smooth out all higher-frequency fluctuations,
 leaving only low-frequency, long term trends.  It also tends to "lag" behind the actual data by a substantial amount,
@@ -151,7 +151,7 @@ although typically less than the `simple` model:
 
 [[linear_100window]]
 .Linear moving average with window of size 100
-image::images/reducers_movavg/linear_100window.png[]
+image::images/pipeline_movavg/linear_100window.png[]
 
 ==== EWMA (Exponentially Weighted)
 
@@ -181,11 +181,11 @@ The default value of `alpha` is `0.5`, and the setting accepts any float from 0-
 
 [[single_0.2alpha]]
 .Single Exponential moving average with window of size 10, alpha = 0.2
-image::images/reducers_movavg/single_0.2alpha.png[]
+image::images/pipeline_movavg/single_0.2alpha.png[]
 
 [[single_0.7alpha]]
 .Single Exponential moving average with window of size 10, alpha = 0.7
-image::images/reducers_movavg/single_0.7alpha.png[]
+image::images/pipeline_movavg/single_0.7alpha.png[]
 
 ==== Holt-Linear
 
@@ -224,11 +224,11 @@ values emphasize short-term trends.  This will become more apparently when you a
 
 [[double_0.2beta]]
 .Double Exponential moving average with window of size 100, alpha = 0.5, beta = 0.2
-image::images/reducers_movavg/double_0.2beta.png[]
+image::images/pipeline_movavg/double_0.2beta.png[]
 
 [[double_0.7beta]]
 .Double Exponential moving average with window of size 100, alpha = 0.5, beta = 0.7
-image::images/reducers_movavg/double_0.7beta.png[]
+image::images/pipeline_movavg/double_0.7beta.png[]
 
 ==== Prediction
 
@@ -256,7 +256,7 @@ of the last value in the series, producing a flat:
 
 [[simple_prediction]]
 .Simple moving average with window of size 10, predict = 50
-image::images/reducers_movavg/simple_prediction.png[]
+image::images/pipeline_movavg/simple_prediction.png[]
 
 In contrast, the `holt` model can extrapolate based on local or global constant trends.  If we set a high `beta`
 value, we can extrapolate based on local constant trends (in this case the predictions head down, because the data at the end
@@ -264,11 +264,11 @@ of the series was heading in a downward direction):
 
 [[double_prediction_local]]
 .Double Exponential moving average with window of size 100, predict = 20, alpha = 0.5, beta = 0.8
-image::images/reducers_movavg/double_prediction_local.png[]
+image::images/pipeline_movavg/double_prediction_local.png[]
 
 In contrast, if we choose a small `beta`, the predictions are based on the global constant trend.  In this series, the
 global trend is slightly positive, so the prediction makes a sharp u-turn and begins a positive slope:
 
 [[double_prediction_global]]
 .Double Exponential moving average with window of size 100, predict = 20, alpha = 0.5, beta = 0.1
-image::images/reducers_movavg/double_prediction_global.png[]
+image::images/pipeline_movavg/double_prediction_global.png[]

docs/reference/aggregations/pipeline/sum-bucket-aggregation.asciidoc

@@ -1,7 +1,7 @@
-[[search-aggregations-reducer-sum-bucket-aggregation]]
+[[search-aggregations-pipeline-sum-bucket-aggregation]]
 === Sum Bucket Aggregation
 
-A sibling reducer aggregation which calculates the sum across all bucket of a specified metric in a sibling aggregation. 
+A sibling pipeline aggregation which calculates the sum across all bucket of a specified metric in a sibling aggregation. 
 The specified metric must be numeric and the sibling aggregation must be a multi-bucket aggregation.
 
 ==== Syntax

src/main/java/org/elasticsearch/action/ActionRequestBuilder.java

@@ -20,6 +20,7 @@
 package org.elasticsearch.action;
 
 import com.google.common.base.Preconditions;
+
 import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.action.support.PlainListenableActionFuture;
 import org.elasticsearch.client.Client;
@@ -27,7 +28,7 @@ import org.elasticsearch.client.ClusterAdminClient;
 import org.elasticsearch.client.ElasticsearchClient;
 import org.elasticsearch.client.IndicesAdminClient;
 import org.elasticsearch.common.unit.TimeValue;
-import org.elasticsearch.search.aggregations.reducers.ReducerBuilder;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregatorBuilder;
 import org.elasticsearch.threadpool.ThreadPool;
 
 /**

src/main/java/org/elasticsearch/action/percolate/PercolateShardResponse.java

@@ -28,9 +28,9 @@ import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.index.shard.ShardId;
 import org.elasticsearch.percolator.PercolateContext;
 import org.elasticsearch.search.aggregations.InternalAggregations;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
-import org.elasticsearch.search.aggregations.reducers.ReducerStreams;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregatorStreams;
-import org.elasticsearch.search.aggregations.reducers.SiblingReducer;
+import org.elasticsearch.search.aggregations.pipeline.SiblingPipelineAggregator;
 import org.elasticsearch.search.highlight.HighlightField;
 import org.elasticsearch.search.query.QuerySearchResult;
 
@@ -56,7 +56,7 @@ public class PercolateShardResponse extends BroadcastShardOperationResponse {
     private int requestedSize;
 
     private InternalAggregations aggregations;
-    private List<SiblingReducer> reducers;
+    private List<SiblingPipelineAggregator> pipelineAggregators;
 
     PercolateShardResponse() {
         hls = new ArrayList<>();
@@ -75,7 +75,7 @@ public class PercolateShardResponse extends BroadcastShardOperationResponse {
             if (result.aggregations() != null) {
                 this.aggregations = (InternalAggregations) result.aggregations();
             }
-            this.reducers = result.reducers();
+            this.pipelineAggregators = result.pipelineAggregators();
         }
     }
 
@@ -119,8 +119,8 @@ public class PercolateShardResponse extends BroadcastShardOperationResponse {
         return aggregations;
     }
 
-    public List<SiblingReducer> reducers() {
+    public List<SiblingPipelineAggregator> pipelineAggregators() {
-        return reducers;
+        return pipelineAggregators;
     }
 
     public byte percolatorTypeId() {
@@ -156,14 +156,14 @@ public class PercolateShardResponse extends BroadcastShardOperationResponse {
         }
         aggregations = InternalAggregations.readOptionalAggregations(in);
         if (in.readBoolean()) {
-            int reducersSize = in.readVInt();
+            int pipelineAggregatorsSize = in.readVInt();
-            List<SiblingReducer> reducers = new ArrayList<>(reducersSize);
+            List<SiblingPipelineAggregator> pipelineAggregators = new ArrayList<>(pipelineAggregatorsSize);
-            for (int i = 0; i < reducersSize; i++) {
+            for (int i = 0; i < pipelineAggregatorsSize; i++) {
                 BytesReference type = in.readBytesReference();
-                Reducer reducer = ReducerStreams.stream(type).readResult(in);
+                PipelineAggregator pipelineAggregator = PipelineAggregatorStreams.stream(type).readResult(in);
-                reducers.add((SiblingReducer) reducer);
+                pipelineAggregators.add((SiblingPipelineAggregator) pipelineAggregator);
             }
-            this.reducers = reducers;
+            this.pipelineAggregators = pipelineAggregators;
         }
     }
 
@@ -190,14 +190,14 @@ public class PercolateShardResponse extends BroadcastShardOperationResponse {
             }
         }
         out.writeOptionalStreamable(aggregations);
-        if (reducers == null) {
+        if (pipelineAggregators == null) {
             out.writeBoolean(false);
         } else {
             out.writeBoolean(true);
-            out.writeVInt(reducers.size());
+            out.writeVInt(pipelineAggregators.size());
-            for (Reducer reducer : reducers) {
+            for (PipelineAggregator pipelineAggregator : pipelineAggregators) {
-                out.writeBytesReference(reducer.type().stream());
+                out.writeBytesReference(pipelineAggregator.type().stream());
-                reducer.writeTo(out);
+                pipelineAggregator.writeTo(out);
             }
         }
     }

src/main/java/org/elasticsearch/percolator/PercolatorService.java

@@ -86,8 +86,8 @@ import org.elasticsearch.search.aggregations.AggregationPhase;
 import org.elasticsearch.search.aggregations.InternalAggregation;
 import org.elasticsearch.search.aggregations.InternalAggregation.ReduceContext;
 import org.elasticsearch.search.aggregations.InternalAggregations;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
-import org.elasticsearch.search.aggregations.reducers.SiblingReducer;
+import org.elasticsearch.search.aggregations.pipeline.SiblingPipelineAggregator;
 import org.elasticsearch.search.highlight.HighlightField;
 import org.elasticsearch.search.highlight.HighlightPhase;
 import org.elasticsearch.search.internal.SearchContext;
@@ -852,11 +852,11 @@ public class PercolatorService extends AbstractComponent {
         }
         InternalAggregations aggregations = InternalAggregations.reduce(aggregationsList, new ReduceContext(bigArrays, scriptService));
         if (aggregations != null) {
-            List<SiblingReducer> reducers = shardResults.get(0).reducers();
+            List<SiblingPipelineAggregator> pipelineAggregators = shardResults.get(0).pipelineAggregators();
-            if (reducers != null) {
+            if (pipelineAggregators != null) {
-                List<InternalAggregation> newAggs = new ArrayList<>(Lists.transform(aggregations.asList(), Reducer.AGGREGATION_TRANFORM_FUNCTION));
+                List<InternalAggregation> newAggs = new ArrayList<>(Lists.transform(aggregations.asList(), PipelineAggregator.AGGREGATION_TRANFORM_FUNCTION));
-                for (SiblingReducer reducer : reducers) {
+                for (SiblingPipelineAggregator pipelineAggregator : pipelineAggregators) {
-                    InternalAggregation newAgg = reducer.doReduce(new InternalAggregations(newAggs), new ReduceContext(bigArrays,
+                    InternalAggregation newAgg = pipelineAggregator.doReduce(new InternalAggregations(newAggs), new ReduceContext(bigArrays,
                             scriptService));
                     newAggs.add(newAgg);
                 }

src/main/java/org/elasticsearch/search/aggregations/AggregationModule.java

@@ -56,14 +56,14 @@ import org.elasticsearch.search.aggregations.metrics.stats.extended.ExtendedStat
 import org.elasticsearch.search.aggregations.metrics.sum.SumParser;
 import org.elasticsearch.search.aggregations.metrics.tophits.TopHitsParser;
 import org.elasticsearch.search.aggregations.metrics.valuecount.ValueCountParser;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
-import org.elasticsearch.search.aggregations.reducers.bucketmetrics.avg.AvgBucketParser;
+import org.elasticsearch.search.aggregations.pipeline.bucketmetrics.avg.AvgBucketParser;
-import org.elasticsearch.search.aggregations.reducers.bucketmetrics.max.MaxBucketParser;
+import org.elasticsearch.search.aggregations.pipeline.bucketmetrics.max.MaxBucketParser;
-import org.elasticsearch.search.aggregations.reducers.bucketmetrics.min.MinBucketParser;
+import org.elasticsearch.search.aggregations.pipeline.bucketmetrics.min.MinBucketParser;
-import org.elasticsearch.search.aggregations.reducers.bucketmetrics.sum.SumBucketParser;
+import org.elasticsearch.search.aggregations.pipeline.bucketmetrics.sum.SumBucketParser;
-import org.elasticsearch.search.aggregations.reducers.derivative.DerivativeParser;
+import org.elasticsearch.search.aggregations.pipeline.derivative.DerivativeParser;
-import org.elasticsearch.search.aggregations.reducers.movavg.MovAvgParser;
+import org.elasticsearch.search.aggregations.pipeline.movavg.MovAvgParser;
-import org.elasticsearch.search.aggregations.reducers.movavg.models.MovAvgModelModule;
+import org.elasticsearch.search.aggregations.pipeline.movavg.models.MovAvgModelModule;
 
 import java.util.List;
 
@@ -73,7 +73,7 @@ import java.util.List;
 public class AggregationModule extends AbstractModule implements SpawnModules{
 
     private List<Class<? extends Aggregator.Parser>> aggParsers = Lists.newArrayList();
-    private List<Class<? extends Reducer.Parser>> reducerParsers = Lists.newArrayList();
+    private List<Class<? extends PipelineAggregator.Parser>> pipelineAggParsers = Lists.newArrayList();
 
     public AggregationModule() {
         aggParsers.add(AvgParser.class);
@@ -108,12 +108,12 @@ public class AggregationModule extends AbstractModule implements SpawnModules{
         aggParsers.add(ScriptedMetricParser.class);
         aggParsers.add(ChildrenParser.class);
 
-        reducerParsers.add(DerivativeParser.class);
+        pipelineAggParsers.add(DerivativeParser.class);
-        reducerParsers.add(MaxBucketParser.class);
+        pipelineAggParsers.add(MaxBucketParser.class);
-        reducerParsers.add(MinBucketParser.class);
+        pipelineAggParsers.add(MinBucketParser.class);
-        reducerParsers.add(AvgBucketParser.class);
+        pipelineAggParsers.add(AvgBucketParser.class);
-        reducerParsers.add(SumBucketParser.class);
+        pipelineAggParsers.add(SumBucketParser.class);
-        reducerParsers.add(MovAvgParser.class);
+        pipelineAggParsers.add(MovAvgParser.class);
     }
 
     /**
@@ -131,9 +131,9 @@ public class AggregationModule extends AbstractModule implements SpawnModules{
         for (Class<? extends Aggregator.Parser> parser : aggParsers) {
             multibinderAggParser.addBinding().to(parser);
         }
-        Multibinder<Reducer.Parser> multibinderReducerParser = Multibinder.newSetBinder(binder(), Reducer.Parser.class);
+        Multibinder<PipelineAggregator.Parser> multibinderPipelineAggParser = Multibinder.newSetBinder(binder(), PipelineAggregator.Parser.class);
-        for (Class<? extends Reducer.Parser> parser : reducerParsers) {
+        for (Class<? extends PipelineAggregator.Parser> parser : pipelineAggParsers) {
-            multibinderReducerParser.addBinding().to(parser);
+            multibinderPipelineAggParser.addBinding().to(parser);
         }
         bind(AggregatorParsers.class).asEagerSingleton();
         bind(AggregationParseElement.class).asEagerSingleton();

src/main/java/org/elasticsearch/search/aggregations/AggregationPhase.java

@@ -23,14 +23,13 @@ import com.google.common.collect.ImmutableMap;
 import org.apache.lucene.search.BooleanClause.Occur;
 import org.apache.lucene.search.BooleanQuery;
 import org.apache.lucene.search.Query;
-import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.common.inject.Inject;
 import org.elasticsearch.common.lucene.search.Queries;
 import org.elasticsearch.search.SearchParseElement;
 import org.elasticsearch.search.SearchPhase;
 import org.elasticsearch.search.aggregations.bucket.global.GlobalAggregator;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
-import org.elasticsearch.search.aggregations.reducers.SiblingReducer;
+import org.elasticsearch.search.aggregations.pipeline.SiblingPipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.internal.SearchContext;
 import org.elasticsearch.search.query.QueryPhaseExecutionException;
@@ -145,19 +144,20 @@ public class AggregationPhase implements SearchPhase {
         }
         context.queryResult().aggregations(new InternalAggregations(aggregations));
         try {
-            List<Reducer> reducers = context.aggregations().factories().createReducers();
+            List<PipelineAggregator> pipelineAggregators = context.aggregations().factories().createPipelineAggregators();
-            List<SiblingReducer> siblingReducers = new ArrayList<>(reducers.size());
+            List<SiblingPipelineAggregator> siblingPipelineAggregators = new ArrayList<>(pipelineAggregators.size());
-            for (Reducer reducer : reducers) {
+            for (PipelineAggregator pipelineAggregator : pipelineAggregators) {
-                if (reducer instanceof SiblingReducer) {
+                if (pipelineAggregator instanceof SiblingPipelineAggregator) {
-                    siblingReducers.add((SiblingReducer) reducer);
+                    siblingPipelineAggregators.add((SiblingPipelineAggregator) pipelineAggregator);
                 } else {
-                    throw new AggregationExecutionException("Invalid reducer named [" + reducer.name() + "] of type ["
+                    throw new AggregationExecutionException("Invalid pipeline aggregation named [" + pipelineAggregator.name()
-                            + reducer.type().name() + "]. Only sibling reducers are allowed at the top level");
+                            + "] of type [" + pipelineAggregator.type().name()
+                            + "]. Only sibling pipeline aggregations are allowed at the top level");
                 }
             }
-            context.queryResult().reducers(siblingReducers);
+            context.queryResult().pipelineAggregators(siblingPipelineAggregators);
         } catch (IOException e) {
-            throw new AggregationExecutionException("Failed to build top level reducers", e);
+            throw new AggregationExecutionException("Failed to build top level pipeline aggregators", e);
         }
 
         // disable aggregations so that they don't run on next pages in case of scrolling

src/main/java/org/elasticsearch/search/aggregations/AggregatorBase.java

@@ -21,7 +21,7 @@ package org.elasticsearch.search.aggregations;
 import org.apache.lucene.index.LeafReaderContext;
 import org.elasticsearch.search.aggregations.bucket.BestBucketsDeferringCollector;
 import org.elasticsearch.search.aggregations.bucket.DeferringBucketCollector;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.internal.SearchContext.Lifetime;
 import org.elasticsearch.search.query.QueryPhaseExecutionException;
@@ -47,7 +47,7 @@ public abstract class AggregatorBase extends Aggregator {
 
     private Map<String, Aggregator> subAggregatorbyName;
     private DeferringBucketCollector recordingWrapper;
-    private final List<Reducer> reducers;
+    private final List<PipelineAggregator> pipelineAggregators;
 
     /**
      * Constructs a new Aggregator.
@@ -59,9 +59,9 @@ public abstract class AggregatorBase extends Aggregator {
      * @param metaData              The metaData associated with this aggregator
      */
     protected AggregatorBase(String name, AggregatorFactories factories, AggregationContext context, Aggregator parent,
-            List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+            List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
         this.name = name;
-        this.reducers = reducers;
+        this.pipelineAggregators = pipelineAggregators;
         this.metaData = metaData;
         this.parent = parent;
         this.context = context;
@@ -116,8 +116,8 @@ public abstract class AggregatorBase extends Aggregator {
         return this.metaData;
     }
 
-    public List<Reducer> reducers() {
+    public List<PipelineAggregator> pipelineAggregators() {
-        return this.reducers;
+        return this.pipelineAggregators;
     }
 
     /**

src/main/java/org/elasticsearch/search/aggregations/AggregatorFactories.java

@@ -18,8 +18,8 @@
  */
 package org.elasticsearch.search.aggregations;
 
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
-import org.elasticsearch.search.aggregations.reducers.ReducerFactory;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregatorFactory;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.aggregations.support.AggregationPath;
 
@@ -41,23 +41,23 @@ public class AggregatorFactories {
 
     private AggregatorFactory parent;
     private AggregatorFactory[] factories;
-    private List<ReducerFactory> reducerFactories;
+    private List<PipelineAggregatorFactory> pipelineAggregatorFactories;
 
     public static Builder builder() {
         return new Builder();
     }
 
-    private AggregatorFactories(AggregatorFactory[] factories, List<ReducerFactory> reducers) {
+    private AggregatorFactories(AggregatorFactory[] factories, List<PipelineAggregatorFactory> pipelineAggregators) {
         this.factories = factories;
-        this.reducerFactories = reducers;
+        this.pipelineAggregatorFactories = pipelineAggregators;
     }
 
-    public List<Reducer> createReducers() throws IOException {
+    public List<PipelineAggregator> createPipelineAggregators() throws IOException {
-        List<Reducer> reducers = new ArrayList<>();
+        List<PipelineAggregator> pipelineAggregators = new ArrayList<>();
-        for (ReducerFactory factory : this.reducerFactories) {
+        for (PipelineAggregatorFactory factory : this.pipelineAggregatorFactories) {
-            reducers.add(factory.create());
+            pipelineAggregators.add(factory.create());
         }
-        return reducers;
+        return pipelineAggregators;
     }
 
     /**
@@ -103,8 +103,8 @@ public class AggregatorFactories {
         for (AggregatorFactory factory : factories) {
             factory.validate();
         }
-        for (ReducerFactory factory : reducerFactories) {
+        for (PipelineAggregatorFactory factory : pipelineAggregatorFactories) {
-            factory.validate(parent, factories, reducerFactories);
+            factory.validate(parent, factories, pipelineAggregatorFactories);
         }
     }
 
@@ -112,10 +112,10 @@ public class AggregatorFactories {
 
         private static final AggregatorFactory[] EMPTY_FACTORIES = new AggregatorFactory[0];
         private static final Aggregator[] EMPTY_AGGREGATORS = new Aggregator[0];
-        private static final List<ReducerFactory> EMPTY_REDUCERS = new ArrayList<>();
+        private static final List<PipelineAggregatorFactory> EMPTY_PIPELINE_AGGREGATORS = new ArrayList<>();
 
         private Empty() {
-            super(EMPTY_FACTORIES, EMPTY_REDUCERS);
+            super(EMPTY_FACTORIES, EMPTY_PIPELINE_AGGREGATORS);
         }
 
         @Override
@@ -134,7 +134,7 @@ public class AggregatorFactories {
 
         private final Set<String> names = new HashSet<>();
         private final List<AggregatorFactory> factories = new ArrayList<>();
-        private final List<ReducerFactory> reducerFactories = new ArrayList<>();
+        private final List<PipelineAggregatorFactory> pipelineAggregatorFactories = new ArrayList<>();
 
         public Builder addAggregator(AggregatorFactory factory) {
             if (!names.add(factory.name)) {
@@ -144,43 +144,43 @@ public class AggregatorFactories {
             return this;
         }
 
-        public Builder addReducer(ReducerFactory reducerFactory) {
+        public Builder addPipelineAggregator(PipelineAggregatorFactory pipelineAggregatorFactory) {
-            this.reducerFactories.add(reducerFactory);
+            this.pipelineAggregatorFactories.add(pipelineAggregatorFactory);
             return this;
         }
 
         public AggregatorFactories build() {
-            if (factories.isEmpty() && reducerFactories.isEmpty()) {
+            if (factories.isEmpty() && pipelineAggregatorFactories.isEmpty()) {
                 return EMPTY;
             }
-            List<ReducerFactory> orderedReducers = resolveReducerOrder(this.reducerFactories, this.factories);
+            List<PipelineAggregatorFactory> orderedpipelineAggregators = resolvePipelineAggregatorOrder(this.pipelineAggregatorFactories, this.factories);
-            return new AggregatorFactories(factories.toArray(new AggregatorFactory[factories.size()]), orderedReducers);
+            return new AggregatorFactories(factories.toArray(new AggregatorFactory[factories.size()]), orderedpipelineAggregators);
         }
 
-        private List<ReducerFactory> resolveReducerOrder(List<ReducerFactory> reducerFactories, List<AggregatorFactory> aggFactories) {
+        private List<PipelineAggregatorFactory> resolvePipelineAggregatorOrder(List<PipelineAggregatorFactory> pipelineAggregatorFactories, List<AggregatorFactory> aggFactories) {
-            Map<String, ReducerFactory> reducerFactoriesMap = new HashMap<>();
+            Map<String, PipelineAggregatorFactory> pipelineAggregatorFactoriesMap = new HashMap<>();
-            for (ReducerFactory factory : reducerFactories) {
+            for (PipelineAggregatorFactory factory : pipelineAggregatorFactories) {
-                reducerFactoriesMap.put(factory.getName(), factory);
+                pipelineAggregatorFactoriesMap.put(factory.getName(), factory);
             }
             Set<String> aggFactoryNames = new HashSet<>();
             for (AggregatorFactory aggFactory : aggFactories) {
                 aggFactoryNames.add(aggFactory.name);
             }
-            List<ReducerFactory> orderedReducers = new LinkedList<>();
+            List<PipelineAggregatorFactory> orderedPipelineAggregatorrs = new LinkedList<>();
-            List<ReducerFactory> unmarkedFactories = new ArrayList<ReducerFactory>(reducerFactories);
+            List<PipelineAggregatorFactory> unmarkedFactories = new ArrayList<PipelineAggregatorFactory>(pipelineAggregatorFactories);
-            Set<ReducerFactory> temporarilyMarked = new HashSet<ReducerFactory>();
+            Set<PipelineAggregatorFactory> temporarilyMarked = new HashSet<PipelineAggregatorFactory>();
             while (!unmarkedFactories.isEmpty()) {
-                ReducerFactory factory = unmarkedFactories.get(0);
+                PipelineAggregatorFactory factory = unmarkedFactories.get(0);
-                resolveReducerOrder(aggFactoryNames, reducerFactoriesMap, orderedReducers, unmarkedFactories, temporarilyMarked, factory);
+                resolvePipelineAggregatorOrder(aggFactoryNames, pipelineAggregatorFactoriesMap, orderedPipelineAggregatorrs, unmarkedFactories, temporarilyMarked, factory);
             }
-            return orderedReducers;
+            return orderedPipelineAggregatorrs;
         }
 
-        private void resolveReducerOrder(Set<String> aggFactoryNames, Map<String, ReducerFactory> reducerFactoriesMap,
+        private void resolvePipelineAggregatorOrder(Set<String> aggFactoryNames, Map<String, PipelineAggregatorFactory> pipelineAggregatorFactoriesMap,
-                List<ReducerFactory> orderedReducers, List<ReducerFactory> unmarkedFactories, Set<ReducerFactory> temporarilyMarked,
+                List<PipelineAggregatorFactory> orderedPipelineAggregators, List<PipelineAggregatorFactory> unmarkedFactories, Set<PipelineAggregatorFactory> temporarilyMarked,
-                ReducerFactory factory) {
+                PipelineAggregatorFactory factory) {
             if (temporarilyMarked.contains(factory)) {
-                throw new IllegalStateException("Cyclical dependancy found with reducer [" + factory.getName() + "]");
+                throw new IllegalStateException("Cyclical dependancy found with pipeline aggregator [" + factory.getName() + "]");
             } else if (unmarkedFactories.contains(factory)) {
                 temporarilyMarked.add(factory);
                 String[] bucketsPaths = factory.getBucketsPaths();
@@ -190,9 +190,9 @@ public class AggregatorFactories {
                     if (bucketsPath.equals("_count") || bucketsPath.equals("_key") || aggFactoryNames.contains(firstAggName)) {
                         continue;
                     } else {
-                        ReducerFactory matchingFactory = reducerFactoriesMap.get(firstAggName);
+                        PipelineAggregatorFactory matchingFactory = pipelineAggregatorFactoriesMap.get(firstAggName);
                         if (matchingFactory != null) {
-                            resolveReducerOrder(aggFactoryNames, reducerFactoriesMap, orderedReducers, unmarkedFactories,
+                            resolvePipelineAggregatorOrder(aggFactoryNames, pipelineAggregatorFactoriesMap, orderedPipelineAggregators, unmarkedFactories,
                                     temporarilyMarked, matchingFactory);
                         } else {
                             throw new IllegalStateException("No aggregation found for path [" + bucketsPath + "]");
@@ -201,7 +201,7 @@ public class AggregatorFactories {
                 }
                 unmarkedFactories.remove(factory);
                 temporarilyMarked.remove(factory);
-                orderedReducers.add(factory);
+                orderedPipelineAggregators.add(factory);
             }
         }
     }

src/main/java/org/elasticsearch/search/aggregations/AggregatorFactory.java

@@ -23,7 +23,7 @@ import org.apache.lucene.search.Scorer;
 import org.elasticsearch.common.lease.Releasables;
 import org.elasticsearch.common.util.BigArrays;
 import org.elasticsearch.common.util.ObjectArray;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.internal.SearchContext.Lifetime;
 
@@ -86,7 +86,7 @@ public abstract class AggregatorFactory {
     }
 
     protected abstract Aggregator createInternal(AggregationContext context, Aggregator parent, boolean collectsFromSingleBucket,
-            List<Reducer> reducers, Map<String, Object> metaData) throws IOException;
+            List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException;
 
     /**
      * Creates the aggregator
@@ -99,7 +99,7 @@ public abstract class AggregatorFactory {
      * @return                      The created aggregator
      */
     public final Aggregator create(AggregationContext context, Aggregator parent, boolean collectsFromSingleBucket) throws IOException {
-        return createInternal(context, parent, collectsFromSingleBucket, this.factories.createReducers(), this.metaData);
+        return createInternal(context, parent, collectsFromSingleBucket, this.factories.createPipelineAggregators(), this.metaData);
     }
 
     public void doValidate() {

src/main/java/org/elasticsearch/search/aggregations/AggregatorParsers.java

@@ -24,8 +24,8 @@ import org.elasticsearch.common.collect.MapBuilder;
 import org.elasticsearch.common.inject.Inject;
 import org.elasticsearch.common.xcontent.XContentParser;
 import org.elasticsearch.search.SearchParseException;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
-import org.elasticsearch.search.aggregations.reducers.ReducerFactory;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregatorFactory;
 import org.elasticsearch.search.internal.SearchContext;
 
 import java.io.IOException;
@@ -41,7 +41,7 @@ public class AggregatorParsers {
 
     public static final Pattern VALID_AGG_NAME = Pattern.compile("[^\\[\\]>]+");
     private final ImmutableMap<String, Aggregator.Parser> aggParsers;
-    private final ImmutableMap<String, Reducer.Parser> reducerParsers;
+    private final ImmutableMap<String, PipelineAggregator.Parser> pipelineAggregatorParsers;
 
 
     /**
@@ -53,17 +53,17 @@ public class AggregatorParsers {
      *            ).
      */
     @Inject
-    public AggregatorParsers(Set<Aggregator.Parser> aggParsers, Set<Reducer.Parser> reducerParsers) {
+    public AggregatorParsers(Set<Aggregator.Parser> aggParsers, Set<PipelineAggregator.Parser> pipelineAggregatorParsers) {
         MapBuilder<String, Aggregator.Parser> aggParsersBuilder = MapBuilder.newMapBuilder();
         for (Aggregator.Parser parser : aggParsers) {
             aggParsersBuilder.put(parser.type(), parser);
         }
         this.aggParsers = aggParsersBuilder.immutableMap();
-        MapBuilder<String, Reducer.Parser> reducerParsersBuilder = MapBuilder.newMapBuilder();
+        MapBuilder<String, PipelineAggregator.Parser> pipelineAggregatorParsersBuilder = MapBuilder.newMapBuilder();
-        for (Reducer.Parser parser : reducerParsers) {
+        for (PipelineAggregator.Parser parser : pipelineAggregatorParsers) {
-            reducerParsersBuilder.put(parser.type(), parser);
+            pipelineAggregatorParsersBuilder.put(parser.type(), parser);
         }
-        this.reducerParsers = reducerParsersBuilder.immutableMap();
+        this.pipelineAggregatorParsers = pipelineAggregatorParsersBuilder.immutableMap();
     }
 
     /**
@@ -77,14 +77,15 @@ public class AggregatorParsers {
     }
 
     /**
-     * Returns the parser that is registered under the given reducer type.
+     * Returns the parser that is registered under the given pipeline aggregator
+     * type.
      * 
      * @param type
-     *            The reducer type
+     *            The pipeline aggregator type
-     * @return The parser associated with the given reducer type.
+     * @return The parser associated with the given pipeline aggregator type.
      */
-    public Reducer.Parser reducer(String type) {
+    public PipelineAggregator.Parser pipelineAggregator(String type) {
-        return reducerParsers.get(type);
+        return pipelineAggregatorParsers.get(type);
     }
 
     /**
@@ -125,7 +126,7 @@ public class AggregatorParsers {
             }
 
             AggregatorFactory aggFactory = null;
-            ReducerFactory reducerFactory = null;
+            PipelineAggregatorFactory pipelineAggregatorFactory = null;
             AggregatorFactories subFactories = null;
 
             Map<String, Object> metaData = null;
@@ -161,20 +162,19 @@ public class AggregatorParsers {
                             throw new SearchParseException(context, "Found two aggregation type definitions in [" + aggregationName + "]: ["
                                 + aggFactory.type + "] and [" + fieldName + "]", parser.getTokenLocation());
                         }
-                        if (reducerFactory != null) {
+                    if (pipelineAggregatorFactory != null) {
-                            // TODO we would need a .type property on reducers too for this error message?
                         throw new SearchParseException(context, "Found two aggregation type definitions in [" + aggregationName + "]: ["
-                                + reducerFactory + "] and [" + fieldName + "]", parser.getTokenLocation());
+                                + pipelineAggregatorFactory + "] and [" + fieldName + "]", parser.getTokenLocation());
                         }
 
                         Aggregator.Parser aggregatorParser = parser(fieldName);
                         if (aggregatorParser == null) {
-                            Reducer.Parser reducerParser = reducer(fieldName);
+                        PipelineAggregator.Parser pipelineAggregatorParser = pipelineAggregator(fieldName);
-                            if (reducerParser == null) {
+                        if (pipelineAggregatorParser == null) {
                                 throw new SearchParseException(context, "Could not find aggregator type [" + fieldName + "] in ["
                                     + aggregationName + "]", parser.getTokenLocation());
                             } else {
-                                reducerFactory = reducerParser.parse(aggregationName, parser, context);
+                            pipelineAggregatorFactory = pipelineAggregatorParser.parse(aggregationName, parser, context);
                             }
                         } else {
                             aggFactory = aggregatorParser.parse(aggregationName, parser, context);
@@ -182,11 +182,11 @@ public class AggregatorParsers {
                 }
             }
 
-            if (aggFactory == null && reducerFactory == null) {
+            if (aggFactory == null && pipelineAggregatorFactory == null) {
                 throw new SearchParseException(context, "Missing definition for aggregation [" + aggregationName + "]",
                         parser.getTokenLocation());
             } else if (aggFactory != null) {
-                assert reducerFactory == null;
+                assert pipelineAggregatorFactory == null;
             if (metaData != null) {
                     aggFactory.setMetaData(metaData);
             }
@@ -201,12 +201,12 @@ public class AggregatorParsers {
 
                 factories.addAggregator(aggFactory);
             } else {
-                assert reducerFactory != null;
+                assert pipelineAggregatorFactory != null;
                 if (subFactories != null) {
                     throw new SearchParseException(context, "Aggregation [" + aggregationName + "] cannot define sub-aggregations",
                             parser.getTokenLocation());
                 }
-                factories.addReducer(reducerFactory);
+                factories.addPipelineAggregator(pipelineAggregatorFactory);
             }
         }
 

src/main/java/org/elasticsearch/search/aggregations/InternalAggregation.java

@@ -31,8 +31,8 @@ import org.elasticsearch.common.xcontent.ToXContent;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentBuilderString;
 import org.elasticsearch.script.ScriptService;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
-import org.elasticsearch.search.aggregations.reducers.ReducerStreams;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregatorStreams;
 import org.elasticsearch.search.aggregations.support.AggregationPath;
 
 import java.io.IOException;
@@ -115,7 +115,7 @@ public abstract class InternalAggregation implements Aggregation, ToXContent, St
 
     protected Map<String, Object> metaData;
 
-    private List<Reducer> reducers;
+    private List<PipelineAggregator> pipelineAggregators;
 
     /** Constructs an un initialized addAggregation (used for serialization) **/
     protected InternalAggregation() {}
@@ -125,9 +125,9 @@ public abstract class InternalAggregation implements Aggregation, ToXContent, St
      *
      * @param name The name of the get.
      */
-    protected InternalAggregation(String name, List<Reducer> reducers, Map<String, Object> metaData) {
+    protected InternalAggregation(String name, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
         this.name = name;
-        this.reducers = reducers;
+        this.pipelineAggregators = pipelineAggregators;
         this.metaData = metaData;
     }
 
@@ -149,8 +149,8 @@ public abstract class InternalAggregation implements Aggregation, ToXContent, St
      */
     public final InternalAggregation reduce(List<InternalAggregation> aggregations, ReduceContext reduceContext) {
         InternalAggregation aggResult = doReduce(aggregations, reduceContext);
-        for (Reducer reducer : reducers) {
+        for (PipelineAggregator pipelineAggregator : pipelineAggregators) {
-            aggResult = reducer.reduce(aggResult, reduceContext);
+            aggResult = pipelineAggregator.reduce(aggResult, reduceContext);
         }
         return aggResult;
     }
@@ -188,8 +188,8 @@ public abstract class InternalAggregation implements Aggregation, ToXContent, St
         return metaData;
     }
 
-    public List<Reducer> reducers() {
+    public List<PipelineAggregator> pipelineAggregators() {
-        return reducers;
+        return pipelineAggregators;
     }
 
     @Override
@@ -210,10 +210,10 @@ public abstract class InternalAggregation implements Aggregation, ToXContent, St
     public final void writeTo(StreamOutput out) throws IOException {
         out.writeString(name);
         out.writeGenericValue(metaData);
-        out.writeVInt(reducers.size());
+        out.writeVInt(pipelineAggregators.size());
-        for (Reducer reducer : reducers) {
+        for (PipelineAggregator pipelineAggregator : pipelineAggregators) {
-            out.writeBytesReference(reducer.type().stream());
+            out.writeBytesReference(pipelineAggregator.type().stream());
-            reducer.writeTo(out);
+            pipelineAggregator.writeTo(out);
         }
         doWriteTo(out);
     }
@@ -226,13 +226,13 @@ public abstract class InternalAggregation implements Aggregation, ToXContent, St
         metaData = in.readMap();
         int size = in.readVInt();
         if (size == 0) {
-            reducers = ImmutableList.of();
+            pipelineAggregators = ImmutableList.of();
         } else {
-            reducers = Lists.newArrayListWithCapacity(size);
+            pipelineAggregators = Lists.newArrayListWithCapacity(size);
             for (int i = 0; i < size; i++) {
                 BytesReference type = in.readBytesReference();
-                Reducer reducer = ReducerStreams.stream(type).readResult(in);
+                PipelineAggregator pipelineAggregator = PipelineAggregatorStreams.stream(type).readResult(in);
-                reducers.add(reducer);
+                pipelineAggregators.add(pipelineAggregator);
             }
         }
         doReadFrom(in);

src/main/java/org/elasticsearch/search/aggregations/InternalMultiBucketAggregation.java

@@ -20,7 +20,7 @@
 package org.elasticsearch.search.aggregations;
 
 import org.elasticsearch.search.aggregations.bucket.MultiBucketsAggregation;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 
 import java.util.List;
 import java.util.Map;
@@ -31,8 +31,8 @@ public abstract class InternalMultiBucketAggregation<A extends InternalMultiBuck
     public InternalMultiBucketAggregation() {
     }
 
-    public InternalMultiBucketAggregation(String name, List<Reducer> reducers, Map<String, Object> metaData) {
+    public InternalMultiBucketAggregation(String name, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
-        super(name, reducers, metaData);
+        super(name, pipelineAggregators, metaData);
     }
 
     /**

src/main/java/org/elasticsearch/search/aggregations/NonCollectingAggregator.java

@@ -20,7 +20,7 @@
 package org.elasticsearch.search.aggregations;
 
 import org.apache.lucene.index.LeafReaderContext;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 
 import java.io.IOException;
@@ -34,13 +34,13 @@ import java.util.Map;
 public abstract class NonCollectingAggregator extends AggregatorBase {
 
     protected NonCollectingAggregator(String name, AggregationContext context, Aggregator parent, AggregatorFactories subFactories,
-            List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+            List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
-        super(name, subFactories, context, parent, reducers, metaData);
+        super(name, subFactories, context, parent, pipelineAggregators, metaData);
     }
 
-    protected NonCollectingAggregator(String name, AggregationContext context, Aggregator parent, List<Reducer> reducers,
+    protected NonCollectingAggregator(String name, AggregationContext context, Aggregator parent,
-            Map<String, Object> metaData) throws IOException {
+            List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
-        this(name, context, parent, AggregatorFactories.EMPTY, reducers, metaData);
+        this(name, context, parent, AggregatorFactories.EMPTY, pipelineAggregators, metaData);
     }
 
     @Override

src/main/java/org/elasticsearch/search/aggregations/TransportAggregationModule.java

@@ -59,16 +59,16 @@ import org.elasticsearch.search.aggregations.metrics.stats.extended.InternalExte
 import org.elasticsearch.search.aggregations.metrics.sum.InternalSum;
 import org.elasticsearch.search.aggregations.metrics.tophits.InternalTopHits;
 import org.elasticsearch.search.aggregations.metrics.valuecount.InternalValueCount;
-import org.elasticsearch.search.aggregations.reducers.InternalSimpleValue;
+import org.elasticsearch.search.aggregations.pipeline.InternalSimpleValue;
-import org.elasticsearch.search.aggregations.reducers.bucketmetrics.InternalBucketMetricValue;
+import org.elasticsearch.search.aggregations.pipeline.bucketmetrics.InternalBucketMetricValue;
-import org.elasticsearch.search.aggregations.reducers.bucketmetrics.avg.AvgBucketReducer;
+import org.elasticsearch.search.aggregations.pipeline.bucketmetrics.avg.AvgBucketPipelineAggregator;
-import org.elasticsearch.search.aggregations.reducers.bucketmetrics.max.MaxBucketReducer;
+import org.elasticsearch.search.aggregations.pipeline.bucketmetrics.max.MaxBucketPipelineAggregator;
-import org.elasticsearch.search.aggregations.reducers.bucketmetrics.min.MinBucketReducer;
+import org.elasticsearch.search.aggregations.pipeline.bucketmetrics.min.MinBucketPipelineAggregator;
-import org.elasticsearch.search.aggregations.reducers.bucketmetrics.sum.SumBucketReducer;
+import org.elasticsearch.search.aggregations.pipeline.bucketmetrics.sum.SumBucketPipelineAggregator;
-import org.elasticsearch.search.aggregations.reducers.derivative.DerivativeReducer;
+import org.elasticsearch.search.aggregations.pipeline.derivative.DerivativePipelineAggregator;
-import org.elasticsearch.search.aggregations.reducers.derivative.InternalDerivative;
+import org.elasticsearch.search.aggregations.pipeline.derivative.InternalDerivative;
-import org.elasticsearch.search.aggregations.reducers.movavg.MovAvgReducer;
+import org.elasticsearch.search.aggregations.pipeline.movavg.MovAvgPipelineAggregator;
-import org.elasticsearch.search.aggregations.reducers.movavg.models.TransportMovAvgModelModule;
+import org.elasticsearch.search.aggregations.pipeline.movavg.models.TransportMovAvgModelModule;
 
 /**
  * A module that registers all the transport streams for the addAggregation
@@ -117,16 +117,16 @@ public class TransportAggregationModule extends AbstractModule implements SpawnM
         InternalGeoBounds.registerStream();
         InternalChildren.registerStream();
 
-        // Reducers
+        // Pipeline Aggregations
-        DerivativeReducer.registerStreams();
+        DerivativePipelineAggregator.registerStreams();
         InternalDerivative.registerStreams();
         InternalSimpleValue.registerStreams();
         InternalBucketMetricValue.registerStreams();
-        MaxBucketReducer.registerStreams();
+        MaxBucketPipelineAggregator.registerStreams();
-        MinBucketReducer.registerStreams();
+        MinBucketPipelineAggregator.registerStreams();
-        AvgBucketReducer.registerStreams();
+        AvgBucketPipelineAggregator.registerStreams();
-        SumBucketReducer.registerStreams();
+        SumBucketPipelineAggregator.registerStreams();
-        MovAvgReducer.registerStreams();
+        MovAvgPipelineAggregator.registerStreams();
     }
 
     @Override

src/main/java/org/elasticsearch/search/aggregations/bucket/BucketsAggregator.java

@@ -27,7 +27,7 @@ import org.elasticsearch.search.aggregations.AggregatorFactories;
 import org.elasticsearch.search.aggregations.InternalAggregation;
 import org.elasticsearch.search.aggregations.InternalAggregations;
 import org.elasticsearch.search.aggregations.LeafBucketCollector;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 
 import java.io.IOException;
@@ -44,8 +44,8 @@ public abstract class BucketsAggregator extends AggregatorBase {
     private IntArray docCounts;
 
     public BucketsAggregator(String name, AggregatorFactories factories, AggregationContext context, Aggregator parent,
-            List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+            List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
-        super(name, factories, context, parent, reducers, metaData);
+        super(name, factories, context, parent, pipelineAggregators, metaData);
         bigArrays = context.bigArrays();
         docCounts = bigArrays.newIntArray(1, true);
     }

src/main/java/org/elasticsearch/search/aggregations/bucket/InternalSingleBucketAggregation.java

@@ -23,7 +23,7 @@ import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.search.aggregations.InternalAggregation;
 import org.elasticsearch.search.aggregations.InternalAggregations;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -47,8 +47,8 @@ public abstract class InternalSingleBucketAggregation extends InternalAggregatio
      * @param docCount      The document count in the single bucket.
      * @param aggregations  The already built sub-aggregations that are associated with the bucket.
      */
-    protected InternalSingleBucketAggregation(String name, long docCount, InternalAggregations aggregations, List<Reducer> reducers, Map<String, Object> metaData) {
+    protected InternalSingleBucketAggregation(String name, long docCount, InternalAggregations aggregations, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
-        super(name, reducers, metaData);
+        super(name, pipelineAggregators, metaData);
         this.docCount = docCount;
         this.aggregations = aggregations;
     }

src/main/java/org/elasticsearch/search/aggregations/bucket/SingleBucketAggregator.java

@@ -20,7 +20,7 @@ package org.elasticsearch.search.aggregations.bucket;
 
 import org.elasticsearch.search.aggregations.Aggregator;
 import org.elasticsearch.search.aggregations.AggregatorFactories;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 
 import java.io.IOException;
@@ -34,8 +34,8 @@ public abstract class SingleBucketAggregator extends BucketsAggregator {
 
     protected SingleBucketAggregator(String name, AggregatorFactories factories,
             AggregationContext aggregationContext, Aggregator parent,
-            List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+            List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
-        super(name, factories, aggregationContext, parent, reducers, metaData);
+        super(name, factories, aggregationContext, parent, pipelineAggregators, metaData);
     }
 
 }

src/main/java/org/elasticsearch/search/aggregations/bucket/children/InternalChildren.java

@@ -23,7 +23,7 @@ import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.search.aggregations.AggregationStreams;
 import org.elasticsearch.search.aggregations.InternalAggregations;
 import org.elasticsearch.search.aggregations.bucket.InternalSingleBucketAggregation;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 
 import java.io.IOException;
 import java.util.List;
@@ -51,9 +51,9 @@ public class InternalChildren extends InternalSingleBucketAggregation implements
     public InternalChildren() {
     }
 
-    public InternalChildren(String name, long docCount, InternalAggregations aggregations, List<Reducer> reducers,
+    public InternalChildren(String name, long docCount, InternalAggregations aggregations, List<PipelineAggregator> pipelineAggregators,
             Map<String, Object> metaData) {
-        super(name, docCount, aggregations, reducers, metaData);
+        super(name, docCount, aggregations, pipelineAggregators, metaData);
     }
 
     @Override
@@ -63,6 +63,6 @@ public class InternalChildren extends InternalSingleBucketAggregation implements
 
     @Override
     protected InternalSingleBucketAggregation newAggregation(String name, long docCount, InternalAggregations subAggregations) {
-        return new InternalChildren(name, docCount, subAggregations, reducers(), getMetaData());
+        return new InternalChildren(name, docCount, subAggregations, pipelineAggregators(), getMetaData());
     }
 }

src/main/java/org/elasticsearch/search/aggregations/bucket/children/ParentToChildrenAggregator.java

@@ -36,7 +36,7 @@ import org.elasticsearch.search.aggregations.InternalAggregation;
 import org.elasticsearch.search.aggregations.LeafBucketCollector;
 import org.elasticsearch.search.aggregations.NonCollectingAggregator;
 import org.elasticsearch.search.aggregations.bucket.SingleBucketAggregator;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.aggregations.support.ValuesSource;
 import org.elasticsearch.search.aggregations.support.ValuesSourceAggregatorFactory;
@@ -74,8 +74,8 @@ public class ParentToChildrenAggregator extends SingleBucketAggregator {
     public ParentToChildrenAggregator(String name, AggregatorFactories factories, AggregationContext aggregationContext,
                                       Aggregator parent, String parentType, Filter childFilter, Filter parentFilter,
                                       ValuesSource.Bytes.WithOrdinals.ParentChild valuesSource,
-            long maxOrd, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+            long maxOrd, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
-        super(name, factories, aggregationContext, parent, reducers, metaData);
+        super(name, factories, aggregationContext, parent, pipelineAggregators, metaData);
         this.parentType = parentType;
         // these two filters are cached in the parser
         this.childFilter = aggregationContext.searchContext().searcher().createNormalizedWeight(childFilter, false);
@@ -88,13 +88,13 @@ public class ParentToChildrenAggregator extends SingleBucketAggregator {
 
     @Override
     public InternalAggregation buildAggregation(long owningBucketOrdinal) throws IOException {
-        return new InternalChildren(name, bucketDocCount(owningBucketOrdinal), bucketAggregations(owningBucketOrdinal), reducers(),
+        return new InternalChildren(name, bucketDocCount(owningBucketOrdinal), bucketAggregations(owningBucketOrdinal), pipelineAggregators(),
                 metaData());
     }
 
     @Override
     public InternalAggregation buildEmptyAggregation() {
-        return new InternalChildren(name, 0, buildEmptySubAggregations(), reducers(), metaData());
+        return new InternalChildren(name, 0, buildEmptySubAggregations(), pipelineAggregators(), metaData());
     }
 
     @Override
@@ -196,13 +196,13 @@ public class ParentToChildrenAggregator extends SingleBucketAggregator {
         }
 
         @Override
-        protected Aggregator createUnmapped(AggregationContext aggregationContext, Aggregator parent, List<Reducer> reducers,
+        protected Aggregator createUnmapped(AggregationContext aggregationContext, Aggregator parent, List<PipelineAggregator> pipelineAggregators,
                 Map<String, Object> metaData) throws IOException {
-            return new NonCollectingAggregator(name, aggregationContext, parent, reducers, metaData) {
+            return new NonCollectingAggregator(name, aggregationContext, parent, pipelineAggregators, metaData) {
 
                 @Override
                 public InternalAggregation buildEmptyAggregation() {
-                    return new InternalChildren(name, 0, buildEmptySubAggregations(), reducers(), metaData());
+                    return new InternalChildren(name, 0, buildEmptySubAggregations(), pipelineAggregators(), metaData());
                 }
 
             };
@@ -210,11 +210,11 @@ public class ParentToChildrenAggregator extends SingleBucketAggregator {
 
         @Override
         protected Aggregator doCreateInternal(ValuesSource.Bytes.WithOrdinals.ParentChild valuesSource,
-                AggregationContext aggregationContext, Aggregator parent, boolean collectsFromSingleBucket, List<Reducer> reducers,
+                AggregationContext aggregationContext, Aggregator parent, boolean collectsFromSingleBucket, List<PipelineAggregator> pipelineAggregators,
                 Map<String, Object> metaData) throws IOException {
             long maxOrd = valuesSource.globalMaxOrd(aggregationContext.searchContext().searcher(), parentType);
             return new ParentToChildrenAggregator(name, factories, aggregationContext, parent, parentType, childFilter, parentFilter,
-                    valuesSource, maxOrd, reducers, metaData);
+                    valuesSource, maxOrd, pipelineAggregators, metaData);
         }
 
     }

src/main/java/org/elasticsearch/search/aggregations/bucket/filter/FilterAggregator.java

@@ -30,7 +30,7 @@ import org.elasticsearch.search.aggregations.InternalAggregation;
 import org.elasticsearch.search.aggregations.LeafBucketCollector;
 import org.elasticsearch.search.aggregations.LeafBucketCollectorBase;
 import org.elasticsearch.search.aggregations.bucket.SingleBucketAggregator;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 
 import java.io.IOException;
@@ -48,9 +48,9 @@ public class FilterAggregator extends SingleBucketAggregator {
                             Query filter,
                             AggregatorFactories factories,
                             AggregationContext aggregationContext,
-                            Aggregator parent, List<Reducer> reducers,
+                            Aggregator parent, List<PipelineAggregator> pipelineAggregators,
                             Map<String, Object> metaData) throws IOException {
-        super(name, factories, aggregationContext, parent, reducers, metaData);
+        super(name, factories, aggregationContext, parent, pipelineAggregators, metaData);
         this.filter = aggregationContext.searchContext().searcher().createNormalizedWeight(filter, false);
     }
 
@@ -71,13 +71,13 @@ public class FilterAggregator extends SingleBucketAggregator {
 
     @Override
     public InternalAggregation buildAggregation(long owningBucketOrdinal) throws IOException {
-        return new InternalFilter(name, bucketDocCount(owningBucketOrdinal), bucketAggregations(owningBucketOrdinal), reducers(),
+        return new InternalFilter(name, bucketDocCount(owningBucketOrdinal), bucketAggregations(owningBucketOrdinal), pipelineAggregators(),
                 metaData());
     }
 
     @Override
     public InternalAggregation buildEmptyAggregation() {
-        return new InternalFilter(name, 0, buildEmptySubAggregations(), reducers(), metaData());
+        return new InternalFilter(name, 0, buildEmptySubAggregations(), pipelineAggregators(), metaData());
     }
 
     public static class Factory extends AggregatorFactory {
@@ -91,8 +91,8 @@ public class FilterAggregator extends SingleBucketAggregator {
 
         @Override
         public Aggregator createInternal(AggregationContext context, Aggregator parent, boolean collectsFromSingleBucket,
-                List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+                List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
-            return new FilterAggregator(name, filter, factories, context, parent, reducers, metaData);
+            return new FilterAggregator(name, filter, factories, context, parent, pipelineAggregators, metaData);
         }
 
     }

src/main/java/org/elasticsearch/search/aggregations/bucket/filter/InternalFilter.java

@@ -22,7 +22,7 @@ import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.search.aggregations.AggregationStreams;
 import org.elasticsearch.search.aggregations.InternalAggregations;
 import org.elasticsearch.search.aggregations.bucket.InternalSingleBucketAggregation;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 
 import java.io.IOException;
 import java.util.List;
@@ -50,8 +50,8 @@ public class InternalFilter extends InternalSingleBucketAggregation implements F
 
     InternalFilter() {} // for serialization
 
-    InternalFilter(String name, long docCount, InternalAggregations subAggregations, List<Reducer> reducers, Map<String, Object> metaData) {
+    InternalFilter(String name, long docCount, InternalAggregations subAggregations, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
-        super(name, docCount, subAggregations, reducers, metaData);
+        super(name, docCount, subAggregations, pipelineAggregators, metaData);
     }
 
     @Override
@@ -61,6 +61,6 @@ public class InternalFilter extends InternalSingleBucketAggregation implements F
 
     @Override
     protected InternalSingleBucketAggregation newAggregation(String name, long docCount, InternalAggregations subAggregations) {
-        return new InternalFilter(name, docCount, subAggregations, reducers(), getMetaData());
+        return new InternalFilter(name, docCount, subAggregations, pipelineAggregators(), getMetaData());
     }
 }

src/main/java/org/elasticsearch/search/aggregations/bucket/filters/FiltersAggregator.java

@@ -34,7 +34,7 @@ import org.elasticsearch.search.aggregations.InternalAggregations;
 import org.elasticsearch.search.aggregations.LeafBucketCollector;
 import org.elasticsearch.search.aggregations.LeafBucketCollectorBase;
 import org.elasticsearch.search.aggregations.bucket.BucketsAggregator;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 
 import java.io.IOException;
@@ -62,9 +62,9 @@ public class FiltersAggregator extends BucketsAggregator {
     private final boolean keyed;
 
     public FiltersAggregator(String name, AggregatorFactories factories, List<KeyedFilter> filters, boolean keyed, AggregationContext aggregationContext,
-            Aggregator parent, List<Reducer> reducers, Map<String, Object> metaData)
+            Aggregator parent, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData)
             throws IOException {
-        super(name, factories, aggregationContext, parent, reducers, metaData);
+        super(name, factories, aggregationContext, parent, pipelineAggregators, metaData);
         this.keyed = keyed;
         this.keys = new String[filters.size()];
         this.filters = new Weight[filters.size()];
@@ -103,7 +103,7 @@ public class FiltersAggregator extends BucketsAggregator {
             InternalFilters.Bucket bucket = new InternalFilters.Bucket(keys[i], bucketDocCount(bucketOrd), bucketAggregations(bucketOrd), keyed);
             buckets.add(bucket);
         }
-        return new InternalFilters(name, buckets, keyed, reducers(), metaData());
+        return new InternalFilters(name, buckets, keyed, pipelineAggregators(), metaData());
     }
 
     @Override
@@ -114,7 +114,7 @@ public class FiltersAggregator extends BucketsAggregator {
             InternalFilters.Bucket bucket = new InternalFilters.Bucket(keys[i], 0, subAggs, keyed);
             buckets.add(bucket);
         }
-        return new InternalFilters(name, buckets, keyed, reducers(), metaData());
+        return new InternalFilters(name, buckets, keyed, pipelineAggregators(), metaData());
     }
 
     final long bucketOrd(long owningBucketOrdinal, int filterOrd) {
@@ -134,8 +134,8 @@ public class FiltersAggregator extends BucketsAggregator {
 
         @Override
         public Aggregator createInternal(AggregationContext context, Aggregator parent, boolean collectsFromSingleBucket,
-                List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+                List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
-            return new FiltersAggregator(name, factories, filters, keyed, context, parent, reducers, metaData);
+            return new FiltersAggregator(name, factories, filters, keyed, context, parent, pipelineAggregators, metaData);
         }
     }
 

src/main/java/org/elasticsearch/search/aggregations/bucket/filters/InternalFilters.java

@@ -32,7 +32,7 @@ import org.elasticsearch.search.aggregations.InternalMultiBucketAggregation;
 import org.elasticsearch.search.aggregations.InternalMultiBucketAggregation.InternalBucket;
 import org.elasticsearch.search.aggregations.bucket.BucketStreamContext;
 import org.elasticsearch.search.aggregations.bucket.BucketStreams;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -165,8 +165,8 @@ public class InternalFilters extends InternalMultiBucketAggregation<InternalFilt
 
     public InternalFilters() {} // for serialization
 
-    public InternalFilters(String name, List<Bucket> buckets, boolean keyed, List<Reducer> reducers, Map<String, Object> metaData) {
+    public InternalFilters(String name, List<Bucket> buckets, boolean keyed, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
-        super(name, reducers, metaData);
+        super(name, pipelineAggregators, metaData);
         this.buckets = buckets;
         this.keyed = keyed;
     }
@@ -178,7 +178,7 @@ public class InternalFilters extends InternalMultiBucketAggregation<InternalFilt
 
     @Override
     public InternalFilters create(List<Bucket> buckets) {
-        return new InternalFilters(this.name, buckets, this.keyed, this.reducers(), this.metaData);
+        return new InternalFilters(this.name, buckets, this.keyed, this.pipelineAggregators(), this.metaData);
     }
 
     @Override
@@ -222,7 +222,7 @@ public class InternalFilters extends InternalMultiBucketAggregation<InternalFilt
             }
         }
 
-        InternalFilters reduced = new InternalFilters(name, new ArrayList<Bucket>(bucketsList.size()), keyed, reducers(), getMetaData());
+        InternalFilters reduced = new InternalFilters(name, new ArrayList<Bucket>(bucketsList.size()), keyed, pipelineAggregators(), getMetaData());
         for (List<Bucket> sameRangeList : bucketsList) {
             reduced.buckets.add((sameRangeList.get(0)).reduce(sameRangeList, reduceContext));
         }

src/main/java/org/elasticsearch/search/aggregations/bucket/geogrid/GeoHashGridAggregator.java

@@ -28,7 +28,7 @@ import org.elasticsearch.search.aggregations.LeafBucketCollectorBase;
 import org.elasticsearch.search.aggregations.InternalAggregations;
 import org.elasticsearch.search.aggregations.LeafBucketCollector;
 import org.elasticsearch.search.aggregations.bucket.BucketsAggregator;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.aggregations.support.ValuesSource;
 
@@ -51,9 +51,9 @@ public class GeoHashGridAggregator extends BucketsAggregator {
     private final LongHash bucketOrds;
 
     public GeoHashGridAggregator(String name, AggregatorFactories factories, ValuesSource.Numeric valuesSource,
-            int requiredSize, int shardSize, AggregationContext aggregationContext, Aggregator parent, List<Reducer> reducers,
+            int requiredSize, int shardSize, AggregationContext aggregationContext, Aggregator parent, List<PipelineAggregator> pipelineAggregators,
             Map<String, Object> metaData) throws IOException {
-        super(name, factories, aggregationContext, parent, reducers, metaData);
+        super(name, factories, aggregationContext, parent, pipelineAggregators, metaData);
         this.valuesSource = valuesSource;
         this.requiredSize = requiredSize;
         this.shardSize = shardSize;
@@ -129,12 +129,12 @@ public class GeoHashGridAggregator extends BucketsAggregator {
             bucket.aggregations = bucketAggregations(bucket.bucketOrd);
             list[i] = bucket;
         }
-        return new InternalGeoHashGrid(name, requiredSize, Arrays.asList(list), reducers(), metaData());
+        return new InternalGeoHashGrid(name, requiredSize, Arrays.asList(list), pipelineAggregators(), metaData());
     }
 
     @Override
     public InternalGeoHashGrid buildEmptyAggregation() {
-        return new InternalGeoHashGrid(name, requiredSize, Collections.<InternalGeoHashGrid.Bucket> emptyList(), reducers(), metaData());
+        return new InternalGeoHashGrid(name, requiredSize, Collections.<InternalGeoHashGrid.Bucket> emptyList(), pipelineAggregators(), metaData());
     }
 
 

src/main/java/org/elasticsearch/search/aggregations/bucket/geogrid/GeoHashGridParser.java

@@ -34,7 +34,7 @@ import org.elasticsearch.search.aggregations.AggregatorFactory;
 import org.elasticsearch.search.aggregations.InternalAggregation;
 import org.elasticsearch.search.aggregations.NonCollectingAggregator;
 import org.elasticsearch.search.aggregations.bucket.BucketUtils;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.aggregations.support.ValuesSource;
 import org.elasticsearch.search.aggregations.support.ValuesSourceAggregatorFactory;
@@ -125,11 +125,11 @@ public class GeoHashGridParser implements Aggregator.Parser {
         }
 
         @Override
-        protected Aggregator createUnmapped(AggregationContext aggregationContext, Aggregator parent, List<Reducer> reducers,
+        protected Aggregator createUnmapped(AggregationContext aggregationContext, Aggregator parent, List<PipelineAggregator> pipelineAggregators,
                 Map<String, Object> metaData) throws IOException {
             final InternalAggregation aggregation = new InternalGeoHashGrid(name, requiredSize,
-                    Collections.<InternalGeoHashGrid.Bucket> emptyList(), reducers, metaData);
+                    Collections.<InternalGeoHashGrid.Bucket> emptyList(), pipelineAggregators, metaData);
-            return new NonCollectingAggregator(name, aggregationContext, parent, reducers, metaData) {
+            return new NonCollectingAggregator(name, aggregationContext, parent, pipelineAggregators, metaData) {
                 public InternalAggregation buildEmptyAggregation() {
                     return aggregation;
                 }
@@ -138,13 +138,13 @@ public class GeoHashGridParser implements Aggregator.Parser {
 
         @Override
         protected Aggregator doCreateInternal(final ValuesSource.GeoPoint valuesSource, AggregationContext aggregationContext,
-                Aggregator parent, boolean collectsFromSingleBucket, List<Reducer> reducers, Map<String, Object> metaData)
+                Aggregator parent, boolean collectsFromSingleBucket, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData)
                 throws IOException {
             if (collectsFromSingleBucket == false) {
                 return asMultiBucketAggregator(this, aggregationContext, parent);
             }
             ValuesSource.Numeric cellIdSource = new CellIdSource(valuesSource, precision);
-            return new GeoHashGridAggregator(name, factories, cellIdSource, requiredSize, shardSize, aggregationContext, parent, reducers,
+            return new GeoHashGridAggregator(name, factories, cellIdSource, requiredSize, shardSize, aggregationContext, parent, pipelineAggregators,
                     metaData);
 
         }

src/main/java/org/elasticsearch/search/aggregations/bucket/geogrid/InternalGeoHashGrid.java

@@ -32,7 +32,7 @@ import org.elasticsearch.search.aggregations.InternalAggregations;
 import org.elasticsearch.search.aggregations.InternalMultiBucketAggregation;
 import org.elasticsearch.search.aggregations.bucket.BucketStreamContext;
 import org.elasticsearch.search.aggregations.bucket.BucketStreams;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -171,9 +171,9 @@ public class InternalGeoHashGrid extends InternalMultiBucketAggregation<Internal
     InternalGeoHashGrid() {
     } // for serialization
 
-    public InternalGeoHashGrid(String name, int requiredSize, Collection<Bucket> buckets, List<Reducer> reducers,
+    public InternalGeoHashGrid(String name, int requiredSize, Collection<Bucket> buckets, List<PipelineAggregator> pipelineAggregators,
             Map<String, Object> metaData) {
-        super(name, reducers, metaData);
+        super(name, pipelineAggregators, metaData);
         this.requiredSize = requiredSize;
         this.buckets = buckets;
     }
@@ -185,7 +185,7 @@ public class InternalGeoHashGrid extends InternalMultiBucketAggregation<Internal
 
     @Override
     public InternalGeoHashGrid create(List<Bucket> buckets) {
-        return new InternalGeoHashGrid(this.name, this.requiredSize, buckets, this.reducers(), this.metaData);
+        return new InternalGeoHashGrid(this.name, this.requiredSize, buckets, this.pipelineAggregators(), this.metaData);
     }
 
     @Override
@@ -229,7 +229,7 @@ public class InternalGeoHashGrid extends InternalMultiBucketAggregation<Internal
         for (int i = ordered.size() - 1; i >= 0; i--) {
             list[i] = ordered.pop();
         }
-        return new InternalGeoHashGrid(getName(), requiredSize, Arrays.asList(list), reducers(), getMetaData());
+        return new InternalGeoHashGrid(getName(), requiredSize, Arrays.asList(list), pipelineAggregators(), getMetaData());
     }
 
     @Override

src/main/java/org/elasticsearch/search/aggregations/bucket/global/GlobalAggregator.java

@@ -27,7 +27,7 @@ import org.elasticsearch.search.aggregations.InternalAggregation;
 import org.elasticsearch.search.aggregations.LeafBucketCollector;
 import org.elasticsearch.search.aggregations.LeafBucketCollectorBase;
 import org.elasticsearch.search.aggregations.bucket.SingleBucketAggregator;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 
 import java.io.IOException;
@@ -39,9 +39,9 @@ import java.util.Map;
  */
 public class GlobalAggregator extends SingleBucketAggregator {
 
-    public GlobalAggregator(String name, AggregatorFactories subFactories, AggregationContext aggregationContext, List<Reducer> reducers,
+    public GlobalAggregator(String name, AggregatorFactories subFactories, AggregationContext aggregationContext, List<PipelineAggregator> pipelineAggregators,
             Map<String, Object> metaData) throws IOException {
-        super(name, subFactories, aggregationContext, null, reducers, metaData);
+        super(name, subFactories, aggregationContext, null, pipelineAggregators, metaData);
     }
 
     @Override
@@ -59,7 +59,7 @@ public class GlobalAggregator extends SingleBucketAggregator {
     @Override
     public InternalAggregation buildAggregation(long owningBucketOrdinal) throws IOException {
         assert owningBucketOrdinal == 0 : "global aggregator can only be a top level aggregator";
-        return new InternalGlobal(name, bucketDocCount(owningBucketOrdinal), bucketAggregations(owningBucketOrdinal), reducers(),
+        return new InternalGlobal(name, bucketDocCount(owningBucketOrdinal), bucketAggregations(owningBucketOrdinal), pipelineAggregators(),
                 metaData());
     }
 
@@ -76,7 +76,7 @@ public class GlobalAggregator extends SingleBucketAggregator {
 
         @Override
         public Aggregator createInternal(AggregationContext context, Aggregator parent, boolean collectsFromSingleBucket,
-                List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+                List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
             if (parent != null) {
                 throw new AggregationExecutionException("Aggregation [" + parent.name() + "] cannot have a global " +
                         "sub-aggregation [" + name + "]. Global aggregations can only be defined as top level aggregations");
@@ -84,7 +84,7 @@ public class GlobalAggregator extends SingleBucketAggregator {
             if (collectsFromSingleBucket == false) {
                 throw new IllegalStateException();
             }
-            return new GlobalAggregator(name, factories, context, reducers, metaData);
+            return new GlobalAggregator(name, factories, context, pipelineAggregators, metaData);
         }
 
     }

src/main/java/org/elasticsearch/search/aggregations/bucket/global/InternalGlobal.java

@@ -22,7 +22,7 @@ import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.search.aggregations.AggregationStreams;
 import org.elasticsearch.search.aggregations.InternalAggregations;
 import org.elasticsearch.search.aggregations.bucket.InternalSingleBucketAggregation;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 
 import java.io.IOException;
 import java.util.List;
@@ -51,8 +51,8 @@ public class InternalGlobal extends InternalSingleBucketAggregation implements G
 
     InternalGlobal() {} // for serialization
 
-    InternalGlobal(String name, long docCount, InternalAggregations aggregations, List<Reducer> reducers, Map<String, Object> metaData) {
+    InternalGlobal(String name, long docCount, InternalAggregations aggregations, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
-        super(name, docCount, aggregations, reducers, metaData);
+        super(name, docCount, aggregations, pipelineAggregators, metaData);
     }
 
     @Override
@@ -62,6 +62,6 @@ public class InternalGlobal extends InternalSingleBucketAggregation implements G
 
     @Override
     protected InternalSingleBucketAggregation newAggregation(String name, long docCount, InternalAggregations subAggregations) {
-        return new InternalGlobal(name, docCount, subAggregations, reducers(), getMetaData());
+        return new InternalGlobal(name, docCount, subAggregations, pipelineAggregators(), getMetaData());
     }
 }

src/main/java/org/elasticsearch/search/aggregations/bucket/histogram/HistogramAggregator.java

@@ -31,7 +31,7 @@ import org.elasticsearch.search.aggregations.InternalAggregation;
 import org.elasticsearch.search.aggregations.LeafBucketCollector;
 import org.elasticsearch.search.aggregations.LeafBucketCollectorBase;
 import org.elasticsearch.search.aggregations.bucket.BucketsAggregator;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.aggregations.support.ValuesSource;
 import org.elasticsearch.search.aggregations.support.ValuesSourceAggregatorFactory;
@@ -62,9 +62,9 @@ public class HistogramAggregator extends BucketsAggregator {
                                boolean keyed, long minDocCount, @Nullable ExtendedBounds extendedBounds,
                                @Nullable ValuesSource.Numeric valuesSource, @Nullable ValueFormatter formatter,
                                InternalHistogram.Factory<?> histogramFactory, AggregationContext aggregationContext,
-                               Aggregator parent, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+                               Aggregator parent, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
 
-        super(name, factories, aggregationContext, parent, reducers, metaData);
+        super(name, factories, aggregationContext, parent, pipelineAggregators, metaData);
         this.rounding = rounding;
         this.order = order;
         this.keyed = keyed;
@@ -130,13 +130,13 @@ public class HistogramAggregator extends BucketsAggregator {
 
         // value source will be null for unmapped fields
         InternalHistogram.EmptyBucketInfo emptyBucketInfo = minDocCount == 0 ? new InternalHistogram.EmptyBucketInfo(rounding, buildEmptySubAggregations(), extendedBounds) : null;
-        return histogramFactory.create(name, buckets, order, minDocCount, emptyBucketInfo, formatter, keyed, reducers(), metaData());
+        return histogramFactory.create(name, buckets, order, minDocCount, emptyBucketInfo, formatter, keyed, pipelineAggregators(), metaData());
     }
 
     @Override
     public InternalAggregation buildEmptyAggregation() {
         InternalHistogram.EmptyBucketInfo emptyBucketInfo = minDocCount == 0 ? new InternalHistogram.EmptyBucketInfo(rounding, buildEmptySubAggregations(), extendedBounds) : null;
-        return histogramFactory.create(name, Collections.emptyList(), order, minDocCount, emptyBucketInfo, formatter, keyed, reducers(),
+        return histogramFactory.create(name, Collections.emptyList(), order, minDocCount, emptyBucketInfo, formatter, keyed, pipelineAggregators(),
                 metaData());
     }
 
@@ -172,15 +172,15 @@ public class HistogramAggregator extends BucketsAggregator {
         }
 
         @Override
-        protected Aggregator createUnmapped(AggregationContext aggregationContext, Aggregator parent, List<Reducer> reducers,
+        protected Aggregator createUnmapped(AggregationContext aggregationContext, Aggregator parent, List<PipelineAggregator> pipelineAggregators,
                 Map<String, Object> metaData) throws IOException {
             return new HistogramAggregator(name, factories, rounding, order, keyed, minDocCount, null, null, config.formatter(),
-                    histogramFactory, aggregationContext, parent, reducers, metaData);
+                    histogramFactory, aggregationContext, parent, pipelineAggregators, metaData);
         }
 
         @Override
         protected Aggregator doCreateInternal(ValuesSource.Numeric valuesSource, AggregationContext aggregationContext, Aggregator parent,
-                boolean collectsFromSingleBucket, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+                boolean collectsFromSingleBucket, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
             if (collectsFromSingleBucket == false) {
                 return asMultiBucketAggregator(this, aggregationContext, parent);
             }
@@ -194,7 +194,7 @@ public class HistogramAggregator extends BucketsAggregator {
                 roundedBounds = extendedBounds.round(rounding);
             }
             return new HistogramAggregator(name, factories, rounding, order, keyed, minDocCount, roundedBounds, valuesSource,
-                    config.formatter(), histogramFactory, aggregationContext, parent, reducers, metaData);
+                    config.formatter(), histogramFactory, aggregationContext, parent, pipelineAggregators, metaData);
         }
 
     }

src/main/java/org/elasticsearch/search/aggregations/bucket/histogram/InternalHistogram.java

@@ -37,7 +37,7 @@ import org.elasticsearch.search.aggregations.InternalAggregations;
 import org.elasticsearch.search.aggregations.InternalMultiBucketAggregation;
 import org.elasticsearch.search.aggregations.bucket.BucketStreamContext;
 import org.elasticsearch.search.aggregations.bucket.BucketStreams;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.format.ValueFormatter;
 import org.elasticsearch.search.aggregations.support.format.ValueFormatterStreams;
 
@@ -243,14 +243,16 @@ public class InternalHistogram<B extends InternalHistogram.Bucket> extends Inter
         }
 
         public InternalHistogram<B> create(String name, List<B> buckets, InternalOrder order, long minDocCount,
-                EmptyBucketInfo emptyBucketInfo, @Nullable ValueFormatter formatter, boolean keyed, List<Reducer> reducers,
+                EmptyBucketInfo emptyBucketInfo, @Nullable ValueFormatter formatter, boolean keyed,
+                List<PipelineAggregator> pipelineAggregators,
                 Map<String, Object> metaData) {
-            return new InternalHistogram<>(name, buckets, order, minDocCount, emptyBucketInfo, formatter, keyed, this, reducers, metaData);
+            return new InternalHistogram<>(name, buckets, order, minDocCount, emptyBucketInfo, formatter, keyed, this, pipelineAggregators,
+                    metaData);
         }
 
         public InternalHistogram<B> create(List<B> buckets, InternalHistogram<B> prototype) {
             return new InternalHistogram<>(prototype.name, buckets, prototype.order, prototype.minDocCount, prototype.emptyBucketInfo,
-                    prototype.formatter, prototype.keyed, this, prototype.reducers(), prototype.metaData);
+                    prototype.formatter, prototype.keyed, this, prototype.pipelineAggregators(), prototype.metaData);
         }
 
         public B createBucket(InternalAggregations aggregations, B prototype) {
@@ -284,8 +286,9 @@ public class InternalHistogram<B extends InternalHistogram.Bucket> extends Inter
 
     InternalHistogram(String name, List<B> buckets, InternalOrder order, long minDocCount,
  EmptyBucketInfo emptyBucketInfo,
-            @Nullable ValueFormatter formatter, boolean keyed, Factory<B> factory, List<Reducer> reducers, Map<String, Object> metaData) {
+            @Nullable ValueFormatter formatter, boolean keyed, Factory<B> factory, List<PipelineAggregator> pipelineAggregators,
-        super(name, reducers, metaData);
+            Map<String, Object> metaData) {
+        super(name, pipelineAggregators, metaData);
         this.buckets = buckets;
         this.order = order;
         assert (minDocCount == 0) == (emptyBucketInfo != null);
@@ -470,7 +473,7 @@ public class InternalHistogram<B extends InternalHistogram.Bucket> extends Inter
             CollectionUtil.introSort(reducedBuckets, order.comparator());
         }
 
-        return getFactory().create(getName(), reducedBuckets, order, minDocCount, emptyBucketInfo, formatter, keyed, reducers(),
+        return getFactory().create(getName(), reducedBuckets, order, minDocCount, emptyBucketInfo, formatter, keyed, pipelineAggregators(),
                 getMetaData());
     }
 

src/main/java/org/elasticsearch/search/aggregations/bucket/missing/InternalMissing.java

@@ -22,7 +22,7 @@ import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.search.aggregations.AggregationStreams;
 import org.elasticsearch.search.aggregations.InternalAggregations;
 import org.elasticsearch.search.aggregations.bucket.InternalSingleBucketAggregation;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 
 import java.io.IOException;
 import java.util.List;
@@ -52,8 +52,8 @@ public class InternalMissing extends InternalSingleBucketAggregation implements
     InternalMissing() {
     }
 
-    InternalMissing(String name, long docCount, InternalAggregations aggregations, List<Reducer> reducers, Map<String, Object> metaData) {
+    InternalMissing(String name, long docCount, InternalAggregations aggregations, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
-        super(name, docCount, aggregations, reducers, metaData);
+        super(name, docCount, aggregations, pipelineAggregators, metaData);
     }
 
     @Override
@@ -63,6 +63,6 @@ public class InternalMissing extends InternalSingleBucketAggregation implements
 
     @Override
     protected InternalSingleBucketAggregation newAggregation(String name, long docCount, InternalAggregations subAggregations) {
-        return new InternalMissing(name, docCount, subAggregations, reducers(), getMetaData());
+        return new InternalMissing(name, docCount, subAggregations, pipelineAggregators(), getMetaData());
     }
 }

src/main/java/org/elasticsearch/search/aggregations/bucket/missing/MissingAggregator.java

@@ -26,7 +26,7 @@ import org.elasticsearch.search.aggregations.InternalAggregation;
 import org.elasticsearch.search.aggregations.LeafBucketCollector;
 import org.elasticsearch.search.aggregations.LeafBucketCollectorBase;
 import org.elasticsearch.search.aggregations.bucket.SingleBucketAggregator;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.aggregations.support.ValuesSource;
 import org.elasticsearch.search.aggregations.support.ValuesSourceAggregatorFactory;
@@ -44,9 +44,9 @@ public class MissingAggregator extends SingleBucketAggregator {
     private final ValuesSource valuesSource;
 
     public MissingAggregator(String name, AggregatorFactories factories, ValuesSource valuesSource,
-            AggregationContext aggregationContext, Aggregator parent, List<Reducer> reducers,
+            AggregationContext aggregationContext, Aggregator parent, List<PipelineAggregator> pipelineAggregators,
             Map<String, Object> metaData) throws IOException {
-        super(name, factories, aggregationContext, parent, reducers, metaData);
+        super(name, factories, aggregationContext, parent, pipelineAggregators, metaData);
         this.valuesSource = valuesSource;
     }
 
@@ -72,13 +72,13 @@ public class MissingAggregator extends SingleBucketAggregator {
 
     @Override
     public InternalAggregation buildAggregation(long owningBucketOrdinal) throws IOException {
-        return new InternalMissing(name, bucketDocCount(owningBucketOrdinal), bucketAggregations(owningBucketOrdinal), reducers(),
+        return new InternalMissing(name, bucketDocCount(owningBucketOrdinal), bucketAggregations(owningBucketOrdinal), pipelineAggregators(),
                 metaData());
     }
 
     @Override
     public InternalAggregation buildEmptyAggregation() {
-        return new InternalMissing(name, 0, buildEmptySubAggregations(), reducers(), metaData());
+        return new InternalMissing(name, 0, buildEmptySubAggregations(), pipelineAggregators(), metaData());
     }
 
     public static class Factory extends ValuesSourceAggregatorFactory<ValuesSource>  {
@@ -88,15 +88,15 @@ public class MissingAggregator extends SingleBucketAggregator {
         }
 
         @Override
-        protected MissingAggregator createUnmapped(AggregationContext aggregationContext, Aggregator parent, List<Reducer> reducers,
+        protected MissingAggregator createUnmapped(AggregationContext aggregationContext, Aggregator parent, List<PipelineAggregator> pipelineAggregators,
                 Map<String, Object> metaData) throws IOException {
-            return new MissingAggregator(name, factories, null, aggregationContext, parent, reducers, metaData);
+            return new MissingAggregator(name, factories, null, aggregationContext, parent, pipelineAggregators, metaData);
         }
 
         @Override
         protected MissingAggregator doCreateInternal(ValuesSource valuesSource, AggregationContext aggregationContext, Aggregator parent,
-                boolean collectsFromSingleBucket, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+                boolean collectsFromSingleBucket, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
-            return new MissingAggregator(name, factories, valuesSource, aggregationContext, parent, reducers, metaData);
+            return new MissingAggregator(name, factories, valuesSource, aggregationContext, parent, pipelineAggregators, metaData);
         }
     }
 

src/main/java/org/elasticsearch/search/aggregations/bucket/nested/InternalNested.java

@@ -22,7 +22,7 @@ import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.search.aggregations.AggregationStreams;
 import org.elasticsearch.search.aggregations.InternalAggregations;
 import org.elasticsearch.search.aggregations.bucket.InternalSingleBucketAggregation;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 
 import java.io.IOException;
 import java.util.List;
@@ -51,9 +51,9 @@ public class InternalNested extends InternalSingleBucketAggregation implements N
     public InternalNested() {
     }
 
-    public InternalNested(String name, long docCount, InternalAggregations aggregations, List<Reducer> reducers,
+    public InternalNested(String name, long docCount, InternalAggregations aggregations, List<PipelineAggregator> pipelineAggregators,
             Map<String, Object> metaData) {
-        super(name, docCount, aggregations, reducers, metaData);
+        super(name, docCount, aggregations, pipelineAggregators, metaData);
     }
 
     @Override
@@ -63,6 +63,6 @@ public class InternalNested extends InternalSingleBucketAggregation implements N
 
     @Override
     protected InternalSingleBucketAggregation newAggregation(String name, long docCount, InternalAggregations subAggregations) {
-        return new InternalNested(name, docCount, subAggregations, reducers(), getMetaData());
+        return new InternalNested(name, docCount, subAggregations, pipelineAggregators(), getMetaData());
     }
 }

src/main/java/org/elasticsearch/search/aggregations/bucket/nested/InternalReverseNested.java

@@ -22,7 +22,7 @@ import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.search.aggregations.AggregationStreams;
 import org.elasticsearch.search.aggregations.InternalAggregations;
 import org.elasticsearch.search.aggregations.bucket.InternalSingleBucketAggregation;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 
 import java.io.IOException;
 import java.util.List;
@@ -51,9 +51,9 @@ public class InternalReverseNested extends InternalSingleBucketAggregation imple
     public InternalReverseNested() {
     }
 
-    public InternalReverseNested(String name, long docCount, InternalAggregations aggregations, List<Reducer> reducers,
+    public InternalReverseNested(String name, long docCount, InternalAggregations aggregations, List<PipelineAggregator> pipelineAggregators,
             Map<String, Object> metaData) {
-        super(name, docCount, aggregations, reducers, metaData);
+        super(name, docCount, aggregations, pipelineAggregators, metaData);
     }
 
     @Override
@@ -63,6 +63,6 @@ public class InternalReverseNested extends InternalSingleBucketAggregation imple
 
     @Override
     protected InternalSingleBucketAggregation newAggregation(String name, long docCount, InternalAggregations subAggregations) {
-        return new InternalReverseNested(name, docCount, subAggregations, reducers(), getMetaData());
+        return new InternalReverseNested(name, docCount, subAggregations, pipelineAggregators(), getMetaData());
     }
 }

src/main/java/org/elasticsearch/search/aggregations/bucket/nested/NestedAggregator.java

@@ -38,7 +38,7 @@ import org.elasticsearch.search.aggregations.LeafBucketCollector;
 import org.elasticsearch.search.aggregations.LeafBucketCollectorBase;
 import org.elasticsearch.search.aggregations.NonCollectingAggregator;
 import org.elasticsearch.search.aggregations.bucket.SingleBucketAggregator;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 
 import java.io.IOException;
@@ -56,8 +56,8 @@ public class NestedAggregator extends SingleBucketAggregator {
     private DocIdSetIterator childDocs;
     private BitSet parentDocs;
 
-    public NestedAggregator(String name, AggregatorFactories factories, ObjectMapper objectMapper, AggregationContext aggregationContext, Aggregator parentAggregator, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+    public NestedAggregator(String name, AggregatorFactories factories, ObjectMapper objectMapper, AggregationContext aggregationContext, Aggregator parentAggregator, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
-        super(name, factories, aggregationContext, parentAggregator, reducers, metaData);
+        super(name, factories, aggregationContext, parentAggregator, pipelineAggregators, metaData);
         childFilter = objectMapper.nestedTypeFilter();
     }
 
@@ -121,13 +121,13 @@ public class NestedAggregator extends SingleBucketAggregator {
         
     @Override
     public InternalAggregation buildAggregation(long owningBucketOrdinal) throws IOException {
-        return new InternalNested(name, bucketDocCount(owningBucketOrdinal), bucketAggregations(owningBucketOrdinal), reducers(),
+        return new InternalNested(name, bucketDocCount(owningBucketOrdinal), bucketAggregations(owningBucketOrdinal), pipelineAggregators(),
                 metaData());
     }
 
         @Override
     public InternalAggregation buildEmptyAggregation() {
-        return new InternalNested(name, 0, buildEmptySubAggregations(), reducers(), metaData());
+        return new InternalNested(name, 0, buildEmptySubAggregations(), pipelineAggregators(), metaData());
     }
 
     private static Filter findClosestNestedPath(Aggregator parent) {
@@ -152,34 +152,34 @@ public class NestedAggregator extends SingleBucketAggregator {
 
         @Override
         public Aggregator createInternal(AggregationContext context, Aggregator parent, boolean collectsFromSingleBucket,
-                List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+                List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
             if (collectsFromSingleBucket == false) {
                 return asMultiBucketAggregator(this, context, parent);
             }
             MapperService.SmartNameObjectMapper mapper = context.searchContext().smartNameObjectMapper(path);
             if (mapper == null) {
-                return new Unmapped(name, context, parent, reducers, metaData);
+                return new Unmapped(name, context, parent, pipelineAggregators, metaData);
             }
             ObjectMapper objectMapper = mapper.mapper();
             if (objectMapper == null) {
-                return new Unmapped(name, context, parent, reducers, metaData);
+                return new Unmapped(name, context, parent, pipelineAggregators, metaData);
             }
             if (!objectMapper.nested().isNested()) {
                 throw new AggregationExecutionException("[nested] nested path [" + path + "] is not nested");
             }
-            return new NestedAggregator(name, factories, objectMapper, context, parent, reducers, metaData);
+            return new NestedAggregator(name, factories, objectMapper, context, parent, pipelineAggregators, metaData);
         }
 
         private final static class Unmapped extends NonCollectingAggregator {
 
-            public Unmapped(String name, AggregationContext context, Aggregator parent, List<Reducer> reducers, Map<String, Object> metaData)
+            public Unmapped(String name, AggregationContext context, Aggregator parent, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData)
                     throws IOException {
-                super(name, context, parent, reducers, metaData);
+                super(name, context, parent, pipelineAggregators, metaData);
             }
 
             @Override
             public InternalAggregation buildEmptyAggregation() {
-                return new InternalNested(name, 0, buildEmptySubAggregations(), reducers(), metaData());
+                return new InternalNested(name, 0, buildEmptySubAggregations(), pipelineAggregators(), metaData());
             }
         }
     }

src/main/java/org/elasticsearch/search/aggregations/bucket/nested/ReverseNestedAggregator.java

@@ -40,7 +40,7 @@ import org.elasticsearch.search.aggregations.LeafBucketCollector;
 import org.elasticsearch.search.aggregations.LeafBucketCollectorBase;
 import org.elasticsearch.search.aggregations.NonCollectingAggregator;
 import org.elasticsearch.search.aggregations.bucket.SingleBucketAggregator;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 
 import java.io.IOException;
@@ -55,9 +55,9 @@ public class ReverseNestedAggregator extends SingleBucketAggregator {
     private final BitDocIdSetFilter parentFilter;
 
     public ReverseNestedAggregator(String name, AggregatorFactories factories, ObjectMapper objectMapper,
-            AggregationContext aggregationContext, Aggregator parent, List<Reducer> reducers, Map<String, Object> metaData)
+            AggregationContext aggregationContext, Aggregator parent, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData)
             throws IOException {
-        super(name, factories, aggregationContext, parent, reducers, metaData);
+        super(name, factories, aggregationContext, parent, pipelineAggregators, metaData);
         if (objectMapper == null) {
             parentFilter = context.searchContext().bitsetFilterCache().getBitDocIdSetFilter(Queries.newNonNestedFilter());
         } else {
@@ -111,13 +111,13 @@ public class ReverseNestedAggregator extends SingleBucketAggregator {
 
     @Override
     public InternalAggregation buildAggregation(long owningBucketOrdinal) throws IOException {
-        return new InternalReverseNested(name, bucketDocCount(owningBucketOrdinal), bucketAggregations(owningBucketOrdinal), reducers(),
+        return new InternalReverseNested(name, bucketDocCount(owningBucketOrdinal), bucketAggregations(owningBucketOrdinal), pipelineAggregators(),
                 metaData());
     }
 
     @Override
     public InternalAggregation buildEmptyAggregation() {
-        return new InternalReverseNested(name, 0, buildEmptySubAggregations(), reducers(), metaData());
+        return new InternalReverseNested(name, 0, buildEmptySubAggregations(), pipelineAggregators(), metaData());
     }
 
     Filter getParentFilter() {
@@ -135,7 +135,7 @@ public class ReverseNestedAggregator extends SingleBucketAggregator {
 
         @Override
         public Aggregator createInternal(AggregationContext context, Aggregator parent, boolean collectsFromSingleBucket,
-                List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+                List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
             // Early validation
             NestedAggregator closestNestedAggregator = findClosestNestedAggregator(parent);
             if (closestNestedAggregator == null) {
@@ -147,11 +147,11 @@ public class ReverseNestedAggregator extends SingleBucketAggregator {
             if (path != null) {
                 MapperService.SmartNameObjectMapper mapper = context.searchContext().smartNameObjectMapper(path);
                 if (mapper == null) {
-                    return new Unmapped(name, context, parent, reducers, metaData);
+                    return new Unmapped(name, context, parent, pipelineAggregators, metaData);
                 }
                 objectMapper = mapper.mapper();
                 if (objectMapper == null) {
-                    return new Unmapped(name, context, parent, reducers, metaData);
+                    return new Unmapped(name, context, parent, pipelineAggregators, metaData);
                 }
                 if (!objectMapper.nested().isNested()) {
                     throw new AggregationExecutionException("[reverse_nested] nested path [" + path + "] is not nested");
@@ -159,19 +159,19 @@ public class ReverseNestedAggregator extends SingleBucketAggregator {
             } else {
                 objectMapper = null;
             }
-            return new ReverseNestedAggregator(name, factories, objectMapper, context, parent, reducers, metaData);
+            return new ReverseNestedAggregator(name, factories, objectMapper, context, parent, pipelineAggregators, metaData);
         }
 
         private final static class Unmapped extends NonCollectingAggregator {
 
-            public Unmapped(String name, AggregationContext context, Aggregator parent, List<Reducer> reducers, Map<String, Object> metaData)
+            public Unmapped(String name, AggregationContext context, Aggregator parent, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData)
                     throws IOException {
-                super(name, context, parent, reducers, metaData);
+                super(name, context, parent, pipelineAggregators, metaData);
             }
 
             @Override
             public InternalAggregation buildEmptyAggregation() {
-                return new InternalReverseNested(name, 0, buildEmptySubAggregations(), reducers(), metaData());
+                return new InternalReverseNested(name, 0, buildEmptySubAggregations(), pipelineAggregators(), metaData());
             }
         }
     }

src/main/java/org/elasticsearch/search/aggregations/bucket/range/InternalRange.java

@@ -31,7 +31,7 @@ import org.elasticsearch.search.aggregations.InternalAggregations;
 import org.elasticsearch.search.aggregations.InternalMultiBucketAggregation;
 import org.elasticsearch.search.aggregations.bucket.BucketStreamContext;
 import org.elasticsearch.search.aggregations.bucket.BucketStreams;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.format.ValueFormatter;
 import org.elasticsearch.search.aggregations.support.format.ValueFormatterStreams;
 
@@ -231,9 +231,9 @@ public class InternalRange<B extends InternalRange.Bucket, R extends InternalRan
             return TYPE.name();
         }
 
-        public R create(String name, List<B> ranges, @Nullable ValueFormatter formatter, boolean keyed, List<Reducer> reducers,
+        public R create(String name, List<B> ranges, @Nullable ValueFormatter formatter, boolean keyed, List<PipelineAggregator> pipelineAggregators,
                 Map<String, Object> metaData) {
-            return (R) new InternalRange<>(name, ranges, formatter, keyed, reducers, metaData);
+            return (R) new InternalRange<>(name, ranges, formatter, keyed, pipelineAggregators, metaData);
         }
 
         public B createBucket(String key, double from, double to, long docCount, InternalAggregations aggregations, boolean keyed,
@@ -242,7 +242,7 @@ public class InternalRange<B extends InternalRange.Bucket, R extends InternalRan
         }
 
         public R create(List<B> ranges, R prototype) {
-            return (R) new InternalRange<>(prototype.name, ranges, prototype.formatter, prototype.keyed, prototype.reducers(),
+            return (R) new InternalRange<>(prototype.name, ranges, prototype.formatter, prototype.keyed, prototype.pipelineAggregators(),
                     prototype.metaData);
         }
 
@@ -260,9 +260,9 @@ public class InternalRange<B extends InternalRange.Bucket, R extends InternalRan
 
     public InternalRange() {} // for serialization
 
-    public InternalRange(String name, List<B> ranges, @Nullable ValueFormatter formatter, boolean keyed, List<Reducer> reducers,
+    public InternalRange(String name, List<B> ranges, @Nullable ValueFormatter formatter, boolean keyed, List<PipelineAggregator> pipelineAggregators,
             Map<String, Object> metaData) {
-        super(name, reducers, metaData);
+        super(name, pipelineAggregators, metaData);
         this.ranges = ranges;
         this.formatter = formatter;
         this.keyed = keyed;
@@ -311,7 +311,7 @@ public class InternalRange<B extends InternalRange.Bucket, R extends InternalRan
         for (int i = 0; i < this.ranges.size(); ++i) {
             ranges.add((B) rangeList[i].get(0).reduce(rangeList[i], reduceContext));
         }
-        return getFactory().create(name, ranges, formatter, keyed, reducers(), getMetaData());
+        return getFactory().create(name, ranges, formatter, keyed, pipelineAggregators(), getMetaData());
     }
 
     @Override

src/main/java/org/elasticsearch/search/aggregations/bucket/range/RangeAggregator.java

@@ -33,7 +33,7 @@ import org.elasticsearch.search.aggregations.InternalAggregations;
 import org.elasticsearch.search.aggregations.LeafBucketCollector;
 import org.elasticsearch.search.aggregations.NonCollectingAggregator;
 import org.elasticsearch.search.aggregations.bucket.BucketsAggregator;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.aggregations.support.ValuesSource;
 import org.elasticsearch.search.aggregations.support.ValuesSourceAggregatorFactory;
@@ -105,10 +105,10 @@ public class RangeAggregator extends BucketsAggregator {
                            List<Range> ranges,
                            boolean keyed,
                            AggregationContext aggregationContext,
-                           Aggregator parent, List<Reducer> reducers,
+                           Aggregator parent, List<PipelineAggregator> pipelineAggregators,
                            Map<String, Object> metaData) throws IOException {
 
-        super(name, factories, aggregationContext, parent, reducers, metaData);
+        super(name, factories, aggregationContext, parent, pipelineAggregators, metaData);
         assert valuesSource != null;
         this.valuesSource = valuesSource;
         this.formatter = format != null ? format.formatter() : null;
@@ -216,7 +216,7 @@ public class RangeAggregator extends BucketsAggregator {
             buckets.add(bucket);
         }
         // value source can be null in the case of unmapped fields
-        return rangeFactory.create(name, buckets, formatter, keyed, reducers(), metaData());
+        return rangeFactory.create(name, buckets, formatter, keyed, pipelineAggregators(), metaData());
     }
 
     @Override
@@ -230,7 +230,7 @@ public class RangeAggregator extends BucketsAggregator {
             buckets.add(bucket);
         }
         // value source can be null in the case of unmapped fields
-        return rangeFactory.create(name, buckets, formatter, keyed, reducers(), metaData());
+        return rangeFactory.create(name, buckets, formatter, keyed, pipelineAggregators(), metaData());
     }
 
     private static final void sortRanges(final Range[] ranges) {
@@ -267,10 +267,10 @@ public class RangeAggregator extends BucketsAggregator {
                         ValueFormat format,
                         AggregationContext context,
                         Aggregator parent,
-                        InternalRange.Factory factory, List<Reducer> reducers,
+                        InternalRange.Factory factory, List<PipelineAggregator> pipelineAggregators,
                         Map<String, Object> metaData) throws IOException {
 
-            super(name, context, parent, reducers, metaData);
+            super(name, context, parent, pipelineAggregators, metaData);
             this.ranges = ranges;
             ValueParser parser = format != null ? format.parser() : ValueParser.RAW;
             for (Range range : this.ranges) {
@@ -288,7 +288,7 @@ public class RangeAggregator extends BucketsAggregator {
             for (RangeAggregator.Range range : ranges) {
                 buckets.add(factory.createBucket(range.key, range.from, range.to, 0, subAggs, keyed, formatter));
             }
-            return factory.create(name, buckets, formatter, keyed, reducers(), metaData());
+            return factory.create(name, buckets, formatter, keyed, pipelineAggregators(), metaData());
         }
     }
 
@@ -306,15 +306,15 @@ public class RangeAggregator extends BucketsAggregator {
         }
 
         @Override
-        protected Aggregator createUnmapped(AggregationContext aggregationContext, Aggregator parent, List<Reducer> reducers,
+        protected Aggregator createUnmapped(AggregationContext aggregationContext, Aggregator parent, List<PipelineAggregator> pipelineAggregators,
                 Map<String, Object> metaData) throws IOException {
-            return new Unmapped(name, ranges, keyed, config.format(), aggregationContext, parent, rangeFactory, reducers, metaData);
+            return new Unmapped(name, ranges, keyed, config.format(), aggregationContext, parent, rangeFactory, pipelineAggregators, metaData);
         }
 
         @Override
         protected Aggregator doCreateInternal(ValuesSource.Numeric valuesSource, AggregationContext aggregationContext, Aggregator parent,
-                boolean collectsFromSingleBucket, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+                boolean collectsFromSingleBucket, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
-            return new RangeAggregator(name, factories, valuesSource, config.format(), rangeFactory, ranges, keyed, aggregationContext, parent, reducers, metaData);
+            return new RangeAggregator(name, factories, valuesSource, config.format(), rangeFactory, ranges, keyed, aggregationContext, parent, pipelineAggregators, metaData);
         }
     }
 

src/main/java/org/elasticsearch/search/aggregations/bucket/range/date/InternalDateRange.java

@@ -26,7 +26,7 @@ import org.elasticsearch.search.aggregations.InternalAggregations;
 import org.elasticsearch.search.aggregations.bucket.BucketStreamContext;
 import org.elasticsearch.search.aggregations.bucket.BucketStreams;
 import org.elasticsearch.search.aggregations.bucket.range.InternalRange;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.format.ValueFormatter;
 import org.joda.time.DateTime;
 import org.joda.time.DateTimeZone;
@@ -122,13 +122,13 @@ public class InternalDateRange extends InternalRange<InternalDateRange.Bucket, I
 
         @Override
         public InternalDateRange create(String name, List<InternalDateRange.Bucket> ranges, ValueFormatter formatter, boolean keyed,
-                List<Reducer> reducers, Map<String, Object> metaData) {
+                List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
-            return new InternalDateRange(name, ranges, formatter, keyed, reducers, metaData);
+            return new InternalDateRange(name, ranges, formatter, keyed, pipelineAggregators, metaData);
         }
 
         @Override
         public InternalDateRange create(List<Bucket> ranges, InternalDateRange prototype) {
-            return new InternalDateRange(prototype.name, ranges, prototype.formatter, prototype.keyed, prototype.reducers(),
+            return new InternalDateRange(prototype.name, ranges, prototype.formatter, prototype.keyed, prototype.pipelineAggregators(),
                     prototype.metaData);
         }
 
@@ -147,8 +147,8 @@ public class InternalDateRange extends InternalRange<InternalDateRange.Bucket, I
     InternalDateRange() {} // for serialization
 
     InternalDateRange(String name, List<InternalDateRange.Bucket> ranges, @Nullable ValueFormatter formatter, boolean keyed,
-            List<Reducer> reducers, Map<String, Object> metaData) {
+            List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
-        super(name, ranges, formatter, keyed, reducers, metaData);
+        super(name, ranges, formatter, keyed, pipelineAggregators, metaData);
     }
 
     @Override

src/main/java/org/elasticsearch/search/aggregations/bucket/range/geodistance/GeoDistanceParser.java

@@ -35,7 +35,7 @@ import org.elasticsearch.search.aggregations.AggregatorFactory;
 import org.elasticsearch.search.aggregations.bucket.range.InternalRange;
 import org.elasticsearch.search.aggregations.bucket.range.RangeAggregator;
 import org.elasticsearch.search.aggregations.bucket.range.RangeAggregator.Unmapped;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.aggregations.support.GeoPointParser;
 import org.elasticsearch.search.aggregations.support.ValuesSource;
@@ -186,18 +186,19 @@ public class GeoDistanceParser implements Aggregator.Parser {
         }
 
         @Override
-        protected Aggregator createUnmapped(AggregationContext aggregationContext, Aggregator parent, List<Reducer> reducers,
+        protected Aggregator createUnmapped(AggregationContext aggregationContext, Aggregator parent, List<PipelineAggregator> pipelineAggregators,
                 Map<String, Object> metaData) throws IOException {
-            return new Unmapped(name, ranges, keyed, null, aggregationContext, parent, rangeFactory, reducers, metaData);
+            return new Unmapped(name, ranges, keyed, null, aggregationContext, parent, rangeFactory, pipelineAggregators, metaData);
         }
 
         @Override
         protected Aggregator doCreateInternal(final ValuesSource.GeoPoint valuesSource, AggregationContext aggregationContext,
-                Aggregator parent, boolean collectsFromSingleBucket, List<Reducer> reducers, Map<String, Object> metaData)
+                Aggregator parent, boolean collectsFromSingleBucket, List<PipelineAggregator> pipelineAggregators,
+                Map<String, Object> metaData)
                 throws IOException {
             DistanceSource distanceSource = new DistanceSource(valuesSource, distanceType, origin, unit);
             return new RangeAggregator(name, factories, distanceSource, null, rangeFactory, ranges, keyed, aggregationContext, parent,
-                    reducers, metaData);
+                    pipelineAggregators, metaData);
         }
 
         private static class DistanceSource extends ValuesSource.Numeric {

src/main/java/org/elasticsearch/search/aggregations/bucket/range/geodistance/InternalGeoDistance.java

@@ -26,7 +26,7 @@ import org.elasticsearch.search.aggregations.InternalAggregations;
 import org.elasticsearch.search.aggregations.bucket.BucketStreamContext;
 import org.elasticsearch.search.aggregations.bucket.BucketStreams;
 import org.elasticsearch.search.aggregations.bucket.range.InternalRange;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.format.ValueFormatter;
 
 import java.io.IOException;
@@ -110,13 +110,13 @@ public class InternalGeoDistance extends InternalRange<InternalGeoDistance.Bucke
 
         @Override
         public InternalGeoDistance create(String name, List<Bucket> ranges, @Nullable ValueFormatter formatter, boolean keyed,
-                List<Reducer> reducers, Map<String, Object> metaData) {
+                List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
-            return new InternalGeoDistance(name, ranges, formatter, keyed, reducers, metaData);
+            return new InternalGeoDistance(name, ranges, formatter, keyed, pipelineAggregators, metaData);
         }
 
         @Override
         public InternalGeoDistance create(List<Bucket> ranges, InternalGeoDistance prototype) {
-            return new InternalGeoDistance(prototype.name, ranges, prototype.formatter, prototype.keyed, prototype.reducers(),
+            return new InternalGeoDistance(prototype.name, ranges, prototype.formatter, prototype.keyed, prototype.pipelineAggregators(),
                     prototype.metaData);
         }
 
@@ -134,9 +134,9 @@ public class InternalGeoDistance extends InternalRange<InternalGeoDistance.Bucke
 
     InternalGeoDistance() {} // for serialization
 
-    public InternalGeoDistance(String name, List<Bucket> ranges, @Nullable ValueFormatter formatter, boolean keyed, List<Reducer> reducers,
+    public InternalGeoDistance(String name, List<Bucket> ranges, @Nullable ValueFormatter formatter, boolean keyed, List<PipelineAggregator> pipelineAggregators,
             Map<String, Object> metaData) {
-        super(name, ranges, formatter, keyed, reducers, metaData);
+        super(name, ranges, formatter, keyed, pipelineAggregators, metaData);
     }
 
     @Override

src/main/java/org/elasticsearch/search/aggregations/bucket/range/ipv4/InternalIPv4Range.java

@@ -26,7 +26,7 @@ import org.elasticsearch.search.aggregations.InternalAggregations;
 import org.elasticsearch.search.aggregations.bucket.BucketStreamContext;
 import org.elasticsearch.search.aggregations.bucket.BucketStreams;
 import org.elasticsearch.search.aggregations.bucket.range.InternalRange;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.format.ValueFormatter;
 
 import java.io.IOException;
@@ -119,13 +119,13 @@ public class InternalIPv4Range extends InternalRange<InternalIPv4Range.Bucket, I
 
         @Override
         public InternalIPv4Range create(String name, List<Bucket> ranges, @Nullable ValueFormatter formatter, boolean keyed,
-                List<Reducer> reducers, Map<String, Object> metaData) {
+                List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
-            return new InternalIPv4Range(name, ranges, keyed, reducers, metaData);
+            return new InternalIPv4Range(name, ranges, keyed, pipelineAggregators, metaData);
         }
 
         @Override
         public InternalIPv4Range create(List<Bucket> ranges, InternalIPv4Range prototype) {
-            return new InternalIPv4Range(prototype.name, ranges, prototype.keyed, prototype.reducers(), prototype.metaData);
+            return new InternalIPv4Range(prototype.name, ranges, prototype.keyed, prototype.pipelineAggregators(), prototype.metaData);
         }
 
         @Override
@@ -142,9 +142,9 @@ public class InternalIPv4Range extends InternalRange<InternalIPv4Range.Bucket, I
 
     public InternalIPv4Range() {} // for serialization
 
-    public InternalIPv4Range(String name, List<InternalIPv4Range.Bucket> ranges, boolean keyed, List<Reducer> reducers,
+    public InternalIPv4Range(String name, List<InternalIPv4Range.Bucket> ranges, boolean keyed, List<PipelineAggregator> pipelineAggregators,
             Map<String, Object> metaData) {
-        super(name, ranges, ValueFormatter.IPv4, keyed, reducers, metaData);
+        super(name, ranges, ValueFormatter.IPv4, keyed, pipelineAggregators, metaData);
     }
 
     @Override

src/main/java/org/elasticsearch/search/aggregations/bucket/sampler/DiversifiedBytesHashSamplerAggregator.java

@@ -31,7 +31,7 @@ import org.elasticsearch.search.aggregations.Aggregator;
 import org.elasticsearch.search.aggregations.AggregatorFactories;
 import org.elasticsearch.search.aggregations.bucket.BestDocsDeferringCollector;
 import org.elasticsearch.search.aggregations.bucket.DeferringBucketCollector;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.aggregations.support.ValuesSource;
 
@@ -49,10 +49,10 @@ public class DiversifiedBytesHashSamplerAggregator extends SamplerAggregator {
     private int maxDocsPerValue;
 
     public DiversifiedBytesHashSamplerAggregator(String name, int shardSize, AggregatorFactories factories,
-            AggregationContext aggregationContext, Aggregator parent, List<Reducer> reducers, Map<String, Object> metaData,
+            AggregationContext aggregationContext, Aggregator parent, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData,
             ValuesSource valuesSource,
             int maxDocsPerValue) throws IOException {
-        super(name, shardSize, factories, aggregationContext, parent, reducers, metaData);
+        super(name, shardSize, factories, aggregationContext, parent, pipelineAggregators, metaData);
         this.valuesSource = valuesSource;
         this.maxDocsPerValue = maxDocsPerValue;
     }

src/main/java/org/elasticsearch/search/aggregations/bucket/sampler/DiversifiedMapSamplerAggregator.java

@@ -33,7 +33,7 @@ import org.elasticsearch.search.aggregations.Aggregator;
 import org.elasticsearch.search.aggregations.AggregatorFactories;
 import org.elasticsearch.search.aggregations.bucket.BestDocsDeferringCollector;
 import org.elasticsearch.search.aggregations.bucket.DeferringBucketCollector;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.aggregations.support.ValuesSource;
 
@@ -48,9 +48,9 @@ public class DiversifiedMapSamplerAggregator extends SamplerAggregator {
     private BytesRefHash bucketOrds;
 
     public DiversifiedMapSamplerAggregator(String name, int shardSize, AggregatorFactories factories,
-            AggregationContext aggregationContext, Aggregator parent, List<Reducer> reducers, Map<String, Object> metaData,
+            AggregationContext aggregationContext, Aggregator parent, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData,
             ValuesSource valuesSource, int maxDocsPerValue) throws IOException {
-        super(name, shardSize, factories, aggregationContext, parent, reducers, metaData);
+        super(name, shardSize, factories, aggregationContext, parent, pipelineAggregators, metaData);
         this.valuesSource = valuesSource;
         this.maxDocsPerValue = maxDocsPerValue;
         bucketOrds = new BytesRefHash(shardSize, aggregationContext.bigArrays());

src/main/java/org/elasticsearch/search/aggregations/bucket/sampler/DiversifiedNumericSamplerAggregator.java

@@ -30,7 +30,7 @@ import org.elasticsearch.search.aggregations.Aggregator;
 import org.elasticsearch.search.aggregations.AggregatorFactories;
 import org.elasticsearch.search.aggregations.bucket.BestDocsDeferringCollector;
 import org.elasticsearch.search.aggregations.bucket.DeferringBucketCollector;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.aggregations.support.ValuesSource;
 
@@ -44,9 +44,9 @@ public class DiversifiedNumericSamplerAggregator extends SamplerAggregator {
     private int maxDocsPerValue;
 
     public DiversifiedNumericSamplerAggregator(String name, int shardSize, AggregatorFactories factories,
-            AggregationContext aggregationContext, Aggregator parent, List<Reducer> reducers, Map<String, Object> metaData,
+            AggregationContext aggregationContext, Aggregator parent, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData,
             ValuesSource.Numeric valuesSource, int maxDocsPerValue) throws IOException {
-        super(name, shardSize, factories, aggregationContext, parent, reducers, metaData);
+        super(name, shardSize, factories, aggregationContext, parent, pipelineAggregators, metaData);
         this.valuesSource = valuesSource;
         this.maxDocsPerValue = maxDocsPerValue;
     }

src/main/java/org/elasticsearch/search/aggregations/bucket/sampler/DiversifiedOrdinalsSamplerAggregator.java

@@ -31,7 +31,7 @@ import org.elasticsearch.search.aggregations.Aggregator;
 import org.elasticsearch.search.aggregations.AggregatorFactories;
 import org.elasticsearch.search.aggregations.bucket.BestDocsDeferringCollector;
 import org.elasticsearch.search.aggregations.bucket.DeferringBucketCollector;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.aggregations.support.ValuesSource;
 
@@ -45,9 +45,9 @@ public class DiversifiedOrdinalsSamplerAggregator extends SamplerAggregator {
     private int maxDocsPerValue;
 
     public DiversifiedOrdinalsSamplerAggregator(String name, int shardSize, AggregatorFactories factories,
-            AggregationContext aggregationContext, Aggregator parent, List<Reducer> reducers, Map<String, Object> metaData,
+            AggregationContext aggregationContext, Aggregator parent, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData,
             ValuesSource.Bytes.WithOrdinals.FieldData valuesSource, int maxDocsPerValue) throws IOException {
-        super(name, shardSize, factories, aggregationContext, parent, reducers, metaData);
+        super(name, shardSize, factories, aggregationContext, parent, pipelineAggregators, metaData);
         this.valuesSource = valuesSource;
         this.maxDocsPerValue = maxDocsPerValue;
     }

src/main/java/org/elasticsearch/search/aggregations/bucket/sampler/InternalSampler.java

@@ -22,7 +22,7 @@ import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.search.aggregations.AggregationStreams;
 import org.elasticsearch.search.aggregations.InternalAggregations;
 import org.elasticsearch.search.aggregations.bucket.InternalSingleBucketAggregation;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 
 import java.io.IOException;
 import java.util.List;
@@ -51,8 +51,8 @@ public class InternalSampler extends InternalSingleBucketAggregation implements
     InternalSampler() {
     } // for serialization
 
-    InternalSampler(String name, long docCount, InternalAggregations subAggregations, List<Reducer> reducers, Map<String, Object> metaData) {
+    InternalSampler(String name, long docCount, InternalAggregations subAggregations, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
-        super(name, docCount, subAggregations, reducers, metaData);
+        super(name, docCount, subAggregations, pipelineAggregators, metaData);
     }
 
     @Override
@@ -63,6 +63,6 @@ public class InternalSampler extends InternalSingleBucketAggregation implements
     @Override
     protected InternalSingleBucketAggregation newAggregation(String name, long docCount,
             InternalAggregations subAggregations) {
-        return new InternalSampler(name, docCount, subAggregations, reducers(), metaData);
+        return new InternalSampler(name, docCount, subAggregations, pipelineAggregators(), metaData);
     }
 }

src/main/java/org/elasticsearch/search/aggregations/bucket/sampler/SamplerAggregator.java

@@ -30,7 +30,7 @@ import org.elasticsearch.search.aggregations.NonCollectingAggregator;
 import org.elasticsearch.search.aggregations.bucket.BestDocsDeferringCollector;
 import org.elasticsearch.search.aggregations.bucket.DeferringBucketCollector;
 import org.elasticsearch.search.aggregations.bucket.SingleBucketAggregator;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.aggregations.support.ValuesSource;
 import org.elasticsearch.search.aggregations.support.ValuesSource.Numeric;
@@ -60,9 +60,11 @@ public class SamplerAggregator extends SingleBucketAggregator {
 
             @Override
             Aggregator create(String name, AggregatorFactories factories, int shardSize, int maxDocsPerValue, ValuesSource valuesSource,
-                    AggregationContext context, Aggregator parent, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+                    AggregationContext context, Aggregator parent, List<PipelineAggregator> pipelineAggregators,
+                    Map<String, Object> metaData) throws IOException {
 
-                return new DiversifiedMapSamplerAggregator(name, shardSize, factories, context, parent, reducers, metaData, valuesSource,
+                return new DiversifiedMapSamplerAggregator(name, shardSize, factories, context, parent, pipelineAggregators, metaData,
+                        valuesSource,
                         maxDocsPerValue);
             }
 
@@ -76,9 +78,11 @@ public class SamplerAggregator extends SingleBucketAggregator {
 
             @Override
             Aggregator create(String name, AggregatorFactories factories, int shardSize, int maxDocsPerValue, ValuesSource valuesSource,
-                    AggregationContext context, Aggregator parent, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+                    AggregationContext context, Aggregator parent, List<PipelineAggregator> pipelineAggregators,
+                    Map<String, Object> metaData) throws IOException {
 
-                return new DiversifiedBytesHashSamplerAggregator(name, shardSize, factories, context, parent, reducers, metaData,
+                return new DiversifiedBytesHashSamplerAggregator(name, shardSize, factories, context, parent, pipelineAggregators,
+                        metaData,
                         valuesSource,
                         maxDocsPerValue);
             }
@@ -93,8 +97,9 @@ public class SamplerAggregator extends SingleBucketAggregator {
 
             @Override
             Aggregator create(String name, AggregatorFactories factories, int shardSize, int maxDocsPerValue, ValuesSource valuesSource,
-                    AggregationContext context, Aggregator parent, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+                    AggregationContext context, Aggregator parent, List<PipelineAggregator> pipelineAggregators,
-                return new DiversifiedOrdinalsSamplerAggregator(name, shardSize, factories, context, parent, reducers, metaData,
+                    Map<String, Object> metaData) throws IOException {
+                return new DiversifiedOrdinalsSamplerAggregator(name, shardSize, factories, context, parent, pipelineAggregators, metaData,
                         (ValuesSource.Bytes.WithOrdinals.FieldData) valuesSource, maxDocsPerValue);
             }
 
@@ -121,7 +126,7 @@ public class SamplerAggregator extends SingleBucketAggregator {
         }
 
         abstract Aggregator create(String name, AggregatorFactories factories, int shardSize, int maxDocsPerValue, ValuesSource valuesSource,
- AggregationContext context, Aggregator parent, List<Reducer> reducers,
+ AggregationContext context, Aggregator parent, List<PipelineAggregator> pipelineAggregators,
                 Map<String, Object> metaData) throws IOException;
 
         abstract boolean needsGlobalOrdinals();
@@ -137,8 +142,8 @@ public class SamplerAggregator extends SingleBucketAggregator {
     protected BestDocsDeferringCollector bdd;
 
     public SamplerAggregator(String name, int shardSize, AggregatorFactories factories, AggregationContext aggregationContext,
-            Aggregator parent, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+            Aggregator parent, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
-        super(name, factories, aggregationContext, parent, reducers, metaData);
+        super(name, factories, aggregationContext, parent, pipelineAggregators, metaData);
         this.shardSize = shardSize;
     }
 
@@ -163,13 +168,13 @@ public class SamplerAggregator extends SingleBucketAggregator {
     @Override
     public InternalAggregation buildAggregation(long owningBucketOrdinal) throws IOException {
         runDeferredCollections(owningBucketOrdinal);
-        return new InternalSampler(name, bdd == null ? 0 : bdd.getDocCount(), bucketAggregations(owningBucketOrdinal), reducers(),
+        return new InternalSampler(name, bdd == null ? 0 : bdd.getDocCount(), bucketAggregations(owningBucketOrdinal), pipelineAggregators(),
                 metaData());
     }
 
     @Override
     public InternalAggregation buildEmptyAggregation() {
-        return new InternalSampler(name, 0, buildEmptySubAggregations(), reducers(), metaData());
+        return new InternalSampler(name, 0, buildEmptySubAggregations(), pipelineAggregators(), metaData());
     }
 
     public static class Factory extends AggregatorFactory {
@@ -183,12 +188,12 @@ public class SamplerAggregator extends SingleBucketAggregator {
 
         @Override
         public Aggregator createInternal(AggregationContext context, Aggregator parent, boolean collectsFromSingleBucket,
-                List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+                List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
 
             if (collectsFromSingleBucket == false) {
                 return asMultiBucketAggregator(this, context, parent);
             }
-            return new SamplerAggregator(name, shardSize, factories, context, parent, reducers, metaData);
+            return new SamplerAggregator(name, shardSize, factories, context, parent, pipelineAggregators, metaData);
         }
 
     }
@@ -208,7 +213,8 @@ public class SamplerAggregator extends SingleBucketAggregator {
 
         @Override
         protected Aggregator doCreateInternal(ValuesSource valuesSource, AggregationContext context, Aggregator parent,
-                boolean collectsFromSingleBucket, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+                boolean collectsFromSingleBucket, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData)
+                throws IOException {
 
             if (collectsFromSingleBucket == false) {
                 return asMultiBucketAggregator(this, context, parent);
@@ -216,7 +222,7 @@ public class SamplerAggregator extends SingleBucketAggregator {
 
 
             if (valuesSource instanceof ValuesSource.Numeric) {
-                return new DiversifiedNumericSamplerAggregator(name, shardSize, factories, context, parent, reducers, metaData,
+                return new DiversifiedNumericSamplerAggregator(name, shardSize, factories, context, parent, pipelineAggregators, metaData,
                         (Numeric) valuesSource, maxDocsPerValue);
             }
             
@@ -234,7 +240,8 @@ public class SamplerAggregator extends SingleBucketAggregator {
                 if ((execution.needsGlobalOrdinals()) && (!(valuesSource instanceof ValuesSource.Bytes.WithOrdinals))) {
                     execution = ExecutionMode.MAP;
                 }
-                return execution.create(name, factories, shardSize, maxDocsPerValue, valuesSource, context, parent, reducers, metaData);
+                return execution.create(name, factories, shardSize, maxDocsPerValue, valuesSource, context, parent, pipelineAggregators,
+                        metaData);
             }
             
             throw new AggregationExecutionException("Sampler aggregation cannot be applied to field [" + config.fieldContext().field() +
@@ -242,11 +249,12 @@ public class SamplerAggregator extends SingleBucketAggregator {
         }
 
         @Override
-        protected Aggregator createUnmapped(AggregationContext aggregationContext, Aggregator parent, List<Reducer> reducers,
+        protected Aggregator createUnmapped(AggregationContext aggregationContext, Aggregator parent,
+                List<PipelineAggregator> pipelineAggregators,
                 Map<String, Object> metaData) throws IOException {
-            final UnmappedSampler aggregation = new UnmappedSampler(name, reducers, metaData);
+            final UnmappedSampler aggregation = new UnmappedSampler(name, pipelineAggregators, metaData);
 
-            return new NonCollectingAggregator(name, aggregationContext, parent, factories, reducers, metaData) {
+            return new NonCollectingAggregator(name, aggregationContext, parent, factories, pipelineAggregators, metaData) {
                 @Override
                 public InternalAggregation buildEmptyAggregation() {
                     return aggregation;

src/main/java/org/elasticsearch/search/aggregations/bucket/sampler/UnmappedSampler.java

@@ -23,7 +23,7 @@ import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.search.aggregations.AggregationStreams;
 import org.elasticsearch.search.aggregations.InternalAggregation;
 import org.elasticsearch.search.aggregations.InternalAggregations;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 
 import java.io.IOException;
 import java.util.List;
@@ -53,8 +53,8 @@ public class UnmappedSampler extends InternalSampler {
     UnmappedSampler() {
     }
 
-    public UnmappedSampler(String name, List<Reducer> reducers, Map<String, Object> metaData) {
+    public UnmappedSampler(String name, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
-        super(name, 0, InternalAggregations.EMPTY, reducers, metaData);
+        super(name, 0, InternalAggregations.EMPTY, pipelineAggregators, metaData);
     }
 
     @Override

src/main/java/org/elasticsearch/search/aggregations/bucket/significant/GlobalOrdinalsSignificantTermsAggregator.java

@@ -29,7 +29,7 @@ import org.elasticsearch.search.aggregations.LeafBucketCollector;
 import org.elasticsearch.search.aggregations.LeafBucketCollectorBase;
 import org.elasticsearch.search.aggregations.bucket.terms.GlobalOrdinalsStringTermsAggregator;
 import org.elasticsearch.search.aggregations.bucket.terms.support.IncludeExclude;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.aggregations.support.ValuesSource;
 import org.elasticsearch.search.internal.ContextIndexSearcher;
@@ -51,10 +51,11 @@ public class GlobalOrdinalsSignificantTermsAggregator extends GlobalOrdinalsStri
     public GlobalOrdinalsSignificantTermsAggregator(String name, AggregatorFactories factories,
             ValuesSource.Bytes.WithOrdinals.FieldData valuesSource, BucketCountThresholds bucketCountThresholds,
             IncludeExclude.OrdinalsFilter includeExclude, AggregationContext aggregationContext, Aggregator parent,
-            SignificantTermsAggregatorFactory termsAggFactory, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+            SignificantTermsAggregatorFactory termsAggFactory, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData)
+            throws IOException {
 
         super(name, factories, valuesSource, null, bucketCountThresholds, includeExclude, aggregationContext, parent,
-                SubAggCollectionMode.DEPTH_FIRST, false, reducers, metaData);
+                SubAggCollectionMode.DEPTH_FIRST, false, pipelineAggregators, metaData);
         this.termsAggFactory = termsAggFactory;
     }
 
@@ -130,7 +131,7 @@ public class GlobalOrdinalsSignificantTermsAggregator extends GlobalOrdinalsStri
         }
 
         return new SignificantStringTerms(subsetSize, supersetSize, name, bucketCountThresholds.getRequiredSize(),
-                bucketCountThresholds.getMinDocCount(), termsAggFactory.getSignificanceHeuristic(), Arrays.asList(list), reducers(),
+                bucketCountThresholds.getMinDocCount(), termsAggFactory.getSignificanceHeuristic(), Arrays.asList(list), pipelineAggregators(),
                 metaData());
     }
 
@@ -142,7 +143,7 @@ public class GlobalOrdinalsSignificantTermsAggregator extends GlobalOrdinalsStri
         int supersetSize = topReader.numDocs();
         return new SignificantStringTerms(0, supersetSize, name, bucketCountThresholds.getRequiredSize(),
                 bucketCountThresholds.getMinDocCount(), termsAggFactory.getSignificanceHeuristic(),
-                Collections.<InternalSignificantTerms.Bucket> emptyList(), reducers(), metaData());
+                Collections.<InternalSignificantTerms.Bucket> emptyList(), pipelineAggregators(), metaData());
     }
 
     @Override
@@ -154,8 +155,12 @@ public class GlobalOrdinalsSignificantTermsAggregator extends GlobalOrdinalsStri
 
         private final LongHash bucketOrds;
 
-        public WithHash(String name, AggregatorFactories factories, ValuesSource.Bytes.WithOrdinals.FieldData valuesSource, BucketCountThresholds bucketCountThresholds, IncludeExclude.OrdinalsFilter includeExclude, AggregationContext aggregationContext, Aggregator parent, SignificantTermsAggregatorFactory termsAggFactory, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+        public WithHash(String name, AggregatorFactories factories, ValuesSource.Bytes.WithOrdinals.FieldData valuesSource,
-            super(name, factories, valuesSource, bucketCountThresholds, includeExclude, aggregationContext, parent, termsAggFactory, reducers, metaData);
+                BucketCountThresholds bucketCountThresholds, IncludeExclude.OrdinalsFilter includeExclude,
+                AggregationContext aggregationContext, Aggregator parent, SignificantTermsAggregatorFactory termsAggFactory,
+                List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
+            super(name, factories, valuesSource, bucketCountThresholds, includeExclude, aggregationContext, parent, termsAggFactory,
+                    pipelineAggregators, metaData);
             bucketOrds = new LongHash(1, aggregationContext.bigArrays());
         }
 

src/main/java/org/elasticsearch/search/aggregations/bucket/significant/InternalSignificantTerms.java

@@ -27,7 +27,7 @@ import org.elasticsearch.search.aggregations.InternalAggregation;
 import org.elasticsearch.search.aggregations.InternalAggregations;
 import org.elasticsearch.search.aggregations.InternalMultiBucketAggregation;
 import org.elasticsearch.search.aggregations.bucket.significant.heuristics.SignificanceHeuristic;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -125,9 +125,9 @@ public abstract class InternalSignificantTerms<A extends InternalSignificantTerm
     }
 
     protected InternalSignificantTerms(long subsetSize, long supersetSize, String name, int requiredSize, long minDocCount,
-            SignificanceHeuristic significanceHeuristic, List<? extends Bucket> buckets, List<Reducer> reducers,
+            SignificanceHeuristic significanceHeuristic, List<? extends Bucket> buckets, List<PipelineAggregator> pipelineAggregators,
             Map<String, Object> metaData) {
-        super(name, reducers, metaData);
+        super(name, pipelineAggregators, metaData);
         this.requiredSize = requiredSize;
         this.minDocCount = minDocCount;
         this.buckets = buckets;

src/main/java/org/elasticsearch/search/aggregations/bucket/significant/SignificantLongTerms.java

@@ -18,7 +18,6 @@
  */
 package org.elasticsearch.search.aggregations.bucket.significant;
 
-import org.elasticsearch.Version;
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
@@ -29,7 +28,7 @@ import org.elasticsearch.search.aggregations.bucket.BucketStreamContext;
 import org.elasticsearch.search.aggregations.bucket.BucketStreams;
 import org.elasticsearch.search.aggregations.bucket.significant.heuristics.SignificanceHeuristic;
 import org.elasticsearch.search.aggregations.bucket.significant.heuristics.SignificanceHeuristicStreams;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.format.ValueFormatter;
 import org.elasticsearch.search.aggregations.support.format.ValueFormatterStreams;
 
@@ -169,9 +168,9 @@ public class SignificantLongTerms extends InternalSignificantTerms<SignificantLo
 
     public SignificantLongTerms(long subsetSize, long supersetSize, String name, @Nullable ValueFormatter formatter, int requiredSize,
             long minDocCount, SignificanceHeuristic significanceHeuristic, List<? extends InternalSignificantTerms.Bucket> buckets,
-            List<Reducer> reducers, Map<String, Object> metaData) {
+            List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
 
-        super(subsetSize, supersetSize, name, requiredSize, minDocCount, significanceHeuristic, buckets, reducers, metaData);
+        super(subsetSize, supersetSize, name, requiredSize, minDocCount, significanceHeuristic, buckets, pipelineAggregators, metaData);
         this.formatter = formatter;
     }
 
@@ -183,7 +182,7 @@ public class SignificantLongTerms extends InternalSignificantTerms<SignificantLo
     @Override
     public SignificantLongTerms create(List<SignificantLongTerms.Bucket> buckets) {
         return new SignificantLongTerms(this.subsetSize, this.supersetSize, this.name, this.formatter, this.requiredSize, this.minDocCount,
-                this.significanceHeuristic, buckets, this.reducers(), this.metaData);
+                this.significanceHeuristic, buckets, this.pipelineAggregators(), this.metaData);
     }
 
     @Override
@@ -197,7 +196,7 @@ public class SignificantLongTerms extends InternalSignificantTerms<SignificantLo
             List<org.elasticsearch.search.aggregations.bucket.significant.InternalSignificantTerms.Bucket> buckets,
             InternalSignificantTerms prototype) {
         return new SignificantLongTerms(subsetSize, supersetSize, prototype.getName(), ((SignificantLongTerms) prototype).formatter,
-                prototype.requiredSize, prototype.minDocCount, prototype.significanceHeuristic, buckets, prototype.reducers(),
+                prototype.requiredSize, prototype.minDocCount, prototype.significanceHeuristic, buckets, prototype.pipelineAggregators(),
                 prototype.getMetaData());
     }
 

src/main/java/org/elasticsearch/search/aggregations/bucket/significant/SignificantLongTermsAggregator.java

@@ -28,7 +28,7 @@ import org.elasticsearch.search.aggregations.LeafBucketCollector;
 import org.elasticsearch.search.aggregations.LeafBucketCollectorBase;
 import org.elasticsearch.search.aggregations.bucket.terms.LongTermsAggregator;
 import org.elasticsearch.search.aggregations.bucket.terms.support.IncludeExclude;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.aggregations.support.ValuesSource;
 import org.elasticsearch.search.aggregations.support.format.ValueFormat;
@@ -48,10 +48,10 @@ public class SignificantLongTermsAggregator extends LongTermsAggregator {
     public SignificantLongTermsAggregator(String name, AggregatorFactories factories, ValuesSource.Numeric valuesSource, @Nullable ValueFormat format,
               BucketCountThresholds bucketCountThresholds, AggregationContext aggregationContext,
               Aggregator parent, SignificantTermsAggregatorFactory termsAggFactory, IncludeExclude.LongFilter includeExclude,
-              List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+            List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
 
         super(name, factories, valuesSource, format, null, bucketCountThresholds, aggregationContext, parent,
-                SubAggCollectionMode.DEPTH_FIRST, false, includeExclude, reducers, metaData);
+                SubAggCollectionMode.DEPTH_FIRST, false, includeExclude, pipelineAggregators, metaData);
         this.termsAggFactory = termsAggFactory;
     }
 
@@ -109,7 +109,7 @@ public class SignificantLongTermsAggregator extends LongTermsAggregator {
             list[i] = bucket;
         }
         return new SignificantLongTerms(subsetSize, supersetSize, name, formatter, bucketCountThresholds.getRequiredSize(),
-                bucketCountThresholds.getMinDocCount(), termsAggFactory.getSignificanceHeuristic(), Arrays.asList(list), reducers(),
+                bucketCountThresholds.getMinDocCount(), termsAggFactory.getSignificanceHeuristic(), Arrays.asList(list), pipelineAggregators(),
                 metaData());
     }
 
@@ -121,7 +121,7 @@ public class SignificantLongTermsAggregator extends LongTermsAggregator {
         int supersetSize = topReader.numDocs();
         return new SignificantLongTerms(0, supersetSize, name, formatter, bucketCountThresholds.getRequiredSize(),
                 bucketCountThresholds.getMinDocCount(), termsAggFactory.getSignificanceHeuristic(),
-                Collections.<InternalSignificantTerms.Bucket> emptyList(), reducers(), metaData());
+                Collections.<InternalSignificantTerms.Bucket> emptyList(), pipelineAggregators(), metaData());
     }
 
     @Override

src/main/java/org/elasticsearch/search/aggregations/bucket/significant/SignificantStringTerms.java

@@ -19,7 +19,6 @@
 package org.elasticsearch.search.aggregations.bucket.significant;
 
 import org.apache.lucene.util.BytesRef;
-import org.elasticsearch.Version;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.xcontent.XContentBuilder;
@@ -30,7 +29,7 @@ import org.elasticsearch.search.aggregations.bucket.BucketStreamContext;
 import org.elasticsearch.search.aggregations.bucket.BucketStreams;
 import org.elasticsearch.search.aggregations.bucket.significant.heuristics.SignificanceHeuristic;
 import org.elasticsearch.search.aggregations.bucket.significant.heuristics.SignificanceHeuristicStreams;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -161,9 +160,10 @@ public class SignificantStringTerms extends InternalSignificantTerms<Significant
     SignificantStringTerms() {} // for serialization
 
     public SignificantStringTerms(long subsetSize, long supersetSize, String name, int requiredSize, long minDocCount,
-            SignificanceHeuristic significanceHeuristic, List<? extends InternalSignificantTerms.Bucket> buckets, List<Reducer> reducers,
+            SignificanceHeuristic significanceHeuristic, List<? extends InternalSignificantTerms.Bucket> buckets,
+            List<PipelineAggregator> pipelineAggregators,
             Map<String, Object> metaData) {
-        super(subsetSize, supersetSize, name, requiredSize, minDocCount, significanceHeuristic, buckets, reducers, metaData);
+        super(subsetSize, supersetSize, name, requiredSize, minDocCount, significanceHeuristic, buckets, pipelineAggregators, metaData);
     }
 
     @Override
@@ -174,7 +174,7 @@ public class SignificantStringTerms extends InternalSignificantTerms<Significant
     @Override
     public SignificantStringTerms create(List<SignificantStringTerms.Bucket> buckets) {
         return new SignificantStringTerms(this.subsetSize, this.supersetSize, this.name, this.requiredSize, this.minDocCount,
-                this.significanceHeuristic, buckets, this.reducers(), this.metaData);
+                this.significanceHeuristic, buckets, this.pipelineAggregators(), this.metaData);
     }
 
     @Override
@@ -187,7 +187,7 @@ public class SignificantStringTerms extends InternalSignificantTerms<Significant
     protected SignificantStringTerms create(long subsetSize, long supersetSize, List<InternalSignificantTerms.Bucket> buckets,
             InternalSignificantTerms prototype) {
         return new SignificantStringTerms(subsetSize, supersetSize, prototype.getName(), prototype.requiredSize, prototype.minDocCount,
-                prototype.significanceHeuristic, buckets, prototype.reducers(), prototype.getMetaData());
+                prototype.significanceHeuristic, buckets, prototype.pipelineAggregators(), prototype.getMetaData());
     }
 
     @Override

src/main/java/org/elasticsearch/search/aggregations/bucket/significant/SignificantStringTermsAggregator.java

@@ -28,7 +28,7 @@ import org.elasticsearch.search.aggregations.LeafBucketCollector;
 import org.elasticsearch.search.aggregations.LeafBucketCollectorBase;
 import org.elasticsearch.search.aggregations.bucket.terms.StringTermsAggregator;
 import org.elasticsearch.search.aggregations.bucket.terms.support.IncludeExclude;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.aggregations.support.ValuesSource;
 import org.elasticsearch.search.internal.ContextIndexSearcher;
@@ -50,11 +50,12 @@ public class SignificantStringTermsAggregator extends StringTermsAggregator {
     public SignificantStringTermsAggregator(String name, AggregatorFactories factories, ValuesSource valuesSource,
             BucketCountThresholds bucketCountThresholds,
             IncludeExclude.StringFilter includeExclude, AggregationContext aggregationContext, Aggregator parent,
-            SignificantTermsAggregatorFactory termsAggFactory, List<Reducer> reducers, Map<String, Object> metaData)
+ SignificantTermsAggregatorFactory termsAggFactory, List<PipelineAggregator> pipelineAggregators,
+            Map<String, Object> metaData)
             throws IOException {
 
         super(name, factories, valuesSource, null, bucketCountThresholds, includeExclude, aggregationContext, parent,
-                SubAggCollectionMode.DEPTH_FIRST, false, reducers, metaData);
+                SubAggCollectionMode.DEPTH_FIRST, false, pipelineAggregators, metaData);
         this.termsAggFactory = termsAggFactory;
     }
 
@@ -115,7 +116,7 @@ public class SignificantStringTermsAggregator extends StringTermsAggregator {
         }
 
         return new SignificantStringTerms(subsetSize, supersetSize, name, bucketCountThresholds.getRequiredSize(),
-                bucketCountThresholds.getMinDocCount(), termsAggFactory.getSignificanceHeuristic(), Arrays.asList(list), reducers(),
+                bucketCountThresholds.getMinDocCount(), termsAggFactory.getSignificanceHeuristic(), Arrays.asList(list), pipelineAggregators(),
                 metaData());
     }
 
@@ -127,7 +128,7 @@ public class SignificantStringTermsAggregator extends StringTermsAggregator {
         int supersetSize = topReader.numDocs();
         return new SignificantStringTerms(0, supersetSize, name, bucketCountThresholds.getRequiredSize(),
                 bucketCountThresholds.getMinDocCount(), termsAggFactory.getSignificanceHeuristic(),
-                Collections.<InternalSignificantTerms.Bucket> emptyList(), reducers(), metaData());
+                Collections.<InternalSignificantTerms.Bucket> emptyList(), pipelineAggregators(), metaData());
     }
 
     @Override

src/main/java/org/elasticsearch/search/aggregations/bucket/significant/SignificantTermsAggregatorFactory.java

@@ -37,7 +37,7 @@ import org.elasticsearch.search.aggregations.NonCollectingAggregator;
 import org.elasticsearch.search.aggregations.bucket.significant.heuristics.SignificanceHeuristic;
 import org.elasticsearch.search.aggregations.bucket.terms.TermsAggregator;
 import org.elasticsearch.search.aggregations.bucket.terms.support.IncludeExclude;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.aggregations.support.ValuesSource;
 import org.elasticsearch.search.aggregations.support.ValuesSourceAggregatorFactory;
@@ -65,10 +65,10 @@ public class SignificantTermsAggregatorFactory extends ValuesSourceAggregatorFac
             Aggregator create(String name, AggregatorFactories factories, ValuesSource valuesSource,
                     TermsAggregator.BucketCountThresholds bucketCountThresholds, IncludeExclude includeExclude,
                     AggregationContext aggregationContext, Aggregator parent, SignificantTermsAggregatorFactory termsAggregatorFactory,
-                    List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+                    List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
                 final IncludeExclude.StringFilter filter = includeExclude == null ? null : includeExclude.convertToStringFilter();
                 return new SignificantStringTermsAggregator(name, factories, valuesSource, bucketCountThresholds, filter,
-                        aggregationContext, parent, termsAggregatorFactory, reducers, metaData);
+                        aggregationContext, parent, termsAggregatorFactory, pipelineAggregators, metaData);
             }
 
         },
@@ -78,11 +78,13 @@ public class SignificantTermsAggregatorFactory extends ValuesSourceAggregatorFac
             Aggregator create(String name, AggregatorFactories factories, ValuesSource valuesSource,
                               TermsAggregator.BucketCountThresholds bucketCountThresholds, IncludeExclude includeExclude,
                     AggregationContext aggregationContext, Aggregator parent, SignificantTermsAggregatorFactory termsAggregatorFactory,
-                    List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+                    List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
                 ValuesSource.Bytes.WithOrdinals valueSourceWithOrdinals = (ValuesSource.Bytes.WithOrdinals) valuesSource;
                 IndexSearcher indexSearcher = aggregationContext.searchContext().searcher();
                 final IncludeExclude.OrdinalsFilter filter = includeExclude == null ? null : includeExclude.convertToOrdinalsFilter();
-                return new GlobalOrdinalsSignificantTermsAggregator(name, factories, (ValuesSource.Bytes.WithOrdinals.FieldData) valuesSource, bucketCountThresholds, filter, aggregationContext, parent, termsAggregatorFactory, reducers, metaData);
+                return new GlobalOrdinalsSignificantTermsAggregator(name, factories,
+                        (ValuesSource.Bytes.WithOrdinals.FieldData) valuesSource, bucketCountThresholds, filter, aggregationContext,
+                        parent, termsAggregatorFactory, pipelineAggregators, metaData);
             }
 
         },
@@ -92,11 +94,12 @@ public class SignificantTermsAggregatorFactory extends ValuesSourceAggregatorFac
             Aggregator create(String name, AggregatorFactories factories, ValuesSource valuesSource,
                               TermsAggregator.BucketCountThresholds bucketCountThresholds, IncludeExclude includeExclude,
                     AggregationContext aggregationContext, Aggregator parent, SignificantTermsAggregatorFactory termsAggregatorFactory,
-                    List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+                    List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
                 final IncludeExclude.OrdinalsFilter filter = includeExclude == null ? null : includeExclude.convertToOrdinalsFilter();
                 return new GlobalOrdinalsSignificantTermsAggregator.WithHash(name, factories,
                         (ValuesSource.Bytes.WithOrdinals.FieldData) valuesSource, bucketCountThresholds, filter,
-                        aggregationContext, parent, termsAggregatorFactory, reducers, metaData);
+ aggregationContext,
+                        parent, termsAggregatorFactory, pipelineAggregators, metaData);
             }
         };
 
@@ -118,7 +121,7 @@ public class SignificantTermsAggregatorFactory extends ValuesSourceAggregatorFac
         abstract Aggregator create(String name, AggregatorFactories factories, ValuesSource valuesSource,
                                    TermsAggregator.BucketCountThresholds bucketCountThresholds, IncludeExclude includeExclude,
                 AggregationContext aggregationContext, Aggregator parent, SignificantTermsAggregatorFactory termsAggregatorFactory,
-                List<Reducer> reducers, Map<String, Object> metaData) throws IOException;
+                List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException;
 
         @Override
         public String toString() {
@@ -155,11 +158,12 @@ public class SignificantTermsAggregatorFactory extends ValuesSourceAggregatorFac
     }
 
     @Override
-    protected Aggregator createUnmapped(AggregationContext aggregationContext, Aggregator parent, List<Reducer> reducers,
+    protected Aggregator createUnmapped(AggregationContext aggregationContext, Aggregator parent,
+            List<PipelineAggregator> pipelineAggregators,
             Map<String, Object> metaData) throws IOException {
         final InternalAggregation aggregation = new UnmappedSignificantTerms(name, bucketCountThresholds.getRequiredSize(),
-                bucketCountThresholds.getMinDocCount(), reducers, metaData);
+                bucketCountThresholds.getMinDocCount(), pipelineAggregators, metaData);
-        return new NonCollectingAggregator(name, aggregationContext, parent, reducers, metaData) {
+        return new NonCollectingAggregator(name, aggregationContext, parent, pipelineAggregators, metaData) {
             @Override
             public InternalAggregation buildEmptyAggregation() {
                 return aggregation;
@@ -169,7 +173,8 @@ public class SignificantTermsAggregatorFactory extends ValuesSourceAggregatorFac
 
     @Override
     protected Aggregator doCreateInternal(ValuesSource valuesSource, AggregationContext aggregationContext, Aggregator parent,
-            boolean collectsFromSingleBucket, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+            boolean collectsFromSingleBucket, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData)
+            throws IOException {
         if (collectsFromSingleBucket == false) {
             return asMultiBucketAggregator(this, aggregationContext, parent);
         }
@@ -193,7 +198,7 @@ public class SignificantTermsAggregatorFactory extends ValuesSourceAggregatorFac
             }
             assert execution != null;
             return execution.create(name, factories, valuesSource, bucketCountThresholds, includeExclude, aggregationContext, parent, this,
-                    reducers, metaData);
+                    pipelineAggregators, metaData);
         }
 
         
@@ -212,7 +217,7 @@ public class SignificantTermsAggregatorFactory extends ValuesSourceAggregatorFac
                 longFilter = includeExclude.convertToLongFilter();
             }
             return new SignificantLongTermsAggregator(name, factories, (ValuesSource.Numeric) valuesSource, config.format(),
-                    bucketCountThresholds, aggregationContext, parent, this, longFilter, reducers, metaData);
+                    bucketCountThresholds, aggregationContext, parent, this, longFilter, pipelineAggregators, metaData);
         }
 
         throw new AggregationExecutionException("sigfnificant_terms aggregation cannot be applied to field [" + config.fieldContext().field() +

src/main/java/org/elasticsearch/search/aggregations/bucket/significant/UnmappedSignificantTerms.java

@@ -25,7 +25,7 @@ import org.elasticsearch.search.aggregations.AggregationStreams;
 import org.elasticsearch.search.aggregations.InternalAggregation;
 import org.elasticsearch.search.aggregations.InternalAggregations;
 import org.elasticsearch.search.aggregations.bucket.significant.heuristics.JLHScore;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -57,10 +57,10 @@ public class UnmappedSignificantTerms extends InternalSignificantTerms<UnmappedS
 
     UnmappedSignificantTerms() {} // for serialization
 
-    public UnmappedSignificantTerms(String name, int requiredSize, long minDocCount, List<Reducer> reducers, Map<String, Object> metaData) {
+    public UnmappedSignificantTerms(String name, int requiredSize, long minDocCount, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
         //We pass zero for index/subset sizes because for the purpose of significant term analysis 
         // we assume an unmapped index's size is irrelevant to the proceedings. 
-        super(0, 0, name, requiredSize, minDocCount, JLHScore.INSTANCE, BUCKETS, reducers, metaData);
+        super(0, 0, name, requiredSize, minDocCount, JLHScore.INSTANCE, BUCKETS, pipelineAggregators, metaData);
     }
 
     @Override
@@ -70,7 +70,7 @@ public class UnmappedSignificantTerms extends InternalSignificantTerms<UnmappedS
 
     @Override
     public UnmappedSignificantTerms create(List<InternalSignificantTerms.Bucket> buckets) {
-        return new UnmappedSignificantTerms(this.name, this.requiredSize, this.minDocCount, this.reducers(), this.metaData);
+        return new UnmappedSignificantTerms(this.name, this.requiredSize, this.minDocCount, this.pipelineAggregators(), this.metaData);
     }
 
     @Override

src/main/java/org/elasticsearch/search/aggregations/bucket/terms/AbstractStringTermsAggregator.java

@@ -22,7 +22,7 @@ package org.elasticsearch.search.aggregations.bucket.terms;
 import org.elasticsearch.search.aggregations.Aggregator;
 import org.elasticsearch.search.aggregations.AggregatorFactories;
 import org.elasticsearch.search.aggregations.InternalAggregation;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 
 import java.io.IOException;
@@ -36,8 +36,8 @@ abstract class AbstractStringTermsAggregator extends TermsAggregator {
 
     public AbstractStringTermsAggregator(String name, AggregatorFactories factories, AggregationContext context, Aggregator parent,
             Terms.Order order, BucketCountThresholds bucketCountThresholds, SubAggCollectionMode subAggCollectMode,
-            boolean showTermDocCountError, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+            boolean showTermDocCountError, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
-        super(name, factories, context, parent, bucketCountThresholds, order, subAggCollectMode, reducers, metaData);
+        super(name, factories, context, parent, bucketCountThresholds, order, subAggCollectMode, pipelineAggregators, metaData);
         this.showTermDocCountError = showTermDocCountError;
     }
 
@@ -45,7 +45,7 @@ abstract class AbstractStringTermsAggregator extends TermsAggregator {
     public InternalAggregation buildEmptyAggregation() {
         return new StringTerms(name, order, bucketCountThresholds.getRequiredSize(), bucketCountThresholds.getShardSize(),
                 bucketCountThresholds.getMinDocCount(), Collections.<InternalTerms.Bucket> emptyList(), showTermDocCountError, 0, 0,
-                reducers(), metaData());
+                pipelineAggregators(), metaData());
     }
 
 }

src/main/java/org/elasticsearch/search/aggregations/bucket/terms/DoubleTerms.java

@@ -27,7 +27,7 @@ import org.elasticsearch.search.aggregations.AggregationStreams;
 import org.elasticsearch.search.aggregations.InternalAggregations;
 import org.elasticsearch.search.aggregations.bucket.BucketStreamContext;
 import org.elasticsearch.search.aggregations.bucket.BucketStreams;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.format.ValueFormatter;
 import org.elasticsearch.search.aggregations.support.format.ValueFormatterStreams;
 
@@ -162,8 +162,8 @@ public class DoubleTerms extends InternalTerms<DoubleTerms, DoubleTerms.Bucket>
 
     public DoubleTerms(String name, Terms.Order order, @Nullable ValueFormatter formatter, int requiredSize, int shardSize,
             long minDocCount, List<? extends InternalTerms.Bucket> buckets, boolean showTermDocCountError, long docCountError,
-            long otherDocCount, List<Reducer> reducers, Map<String, Object> metaData) {
+            long otherDocCount, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
-        super(name, order, requiredSize, shardSize, minDocCount, buckets, showTermDocCountError, docCountError, otherDocCount, reducers,
+        super(name, order, requiredSize, shardSize, minDocCount, buckets, showTermDocCountError, docCountError, otherDocCount, pipelineAggregators,
                 metaData);
         this.formatter = formatter;
     }
@@ -176,7 +176,7 @@ public class DoubleTerms extends InternalTerms<DoubleTerms, DoubleTerms.Bucket>
     @Override
     public DoubleTerms create(List<Bucket> buckets) {
         return new DoubleTerms(this.name, this.order, this.formatter, this.requiredSize, this.shardSize, this.minDocCount, buckets,
-                this.showTermDocCountError, this.docCountError, this.otherDocCount, this.reducers(), this.metaData);
+                this.showTermDocCountError, this.docCountError, this.otherDocCount, this.pipelineAggregators(), this.metaData);
     }
 
     @Override
@@ -189,7 +189,7 @@ public class DoubleTerms extends InternalTerms<DoubleTerms, DoubleTerms.Bucket>
     protected DoubleTerms create(String name, List<org.elasticsearch.search.aggregations.bucket.terms.InternalTerms.Bucket> buckets,
             long docCountError, long otherDocCount, InternalTerms prototype) {
         return new DoubleTerms(name, prototype.order, ((DoubleTerms) prototype).formatter, prototype.requiredSize, prototype.shardSize,
-                prototype.minDocCount, buckets, prototype.showTermDocCountError, docCountError, otherDocCount, prototype.reducers(),
+                prototype.minDocCount, buckets, prototype.showTermDocCountError, docCountError, otherDocCount, prototype.pipelineAggregators(),
                 prototype.getMetaData());
     }
 

src/main/java/org/elasticsearch/search/aggregations/bucket/terms/DoubleTermsAggregator.java

@@ -26,7 +26,7 @@ import org.elasticsearch.index.fielddata.FieldData;
 import org.elasticsearch.search.aggregations.Aggregator;
 import org.elasticsearch.search.aggregations.AggregatorFactories;
 import org.elasticsearch.search.aggregations.bucket.terms.support.IncludeExclude;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.aggregations.support.ValuesSource;
 import org.elasticsearch.search.aggregations.support.ValuesSource.Numeric;
@@ -45,9 +45,9 @@ public class DoubleTermsAggregator extends LongTermsAggregator {
     public DoubleTermsAggregator(String name, AggregatorFactories factories, ValuesSource.Numeric valuesSource, @Nullable ValueFormat format,
             Terms.Order order, BucketCountThresholds bucketCountThresholds,
             AggregationContext aggregationContext, Aggregator parent, SubAggCollectionMode collectionMode, boolean showTermDocCountError,
-            IncludeExclude.LongFilter longFilter, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+            IncludeExclude.LongFilter longFilter, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
         super(name, factories, valuesSource, format, order, bucketCountThresholds, aggregationContext, parent, collectionMode,
-                showTermDocCountError, longFilter, reducers, metaData);
+                showTermDocCountError, longFilter, pipelineAggregators, metaData);
     }
 
     @Override
@@ -79,7 +79,7 @@ public class DoubleTermsAggregator extends LongTermsAggregator {
             buckets[i] = convertToDouble(buckets[i]);
         }
         return new DoubleTerms(terms.getName(), terms.order, terms.formatter, terms.requiredSize, terms.shardSize, terms.minDocCount,
-                Arrays.asList(buckets), terms.showTermDocCountError, terms.docCountError, terms.otherDocCount, terms.reducers(),
+                Arrays.asList(buckets), terms.showTermDocCountError, terms.docCountError, terms.otherDocCount, terms.pipelineAggregators(),
                 terms.getMetaData());
     }
 

src/main/java/org/elasticsearch/search/aggregations/bucket/terms/GlobalOrdinalsStringTermsAggregator.java

@@ -44,7 +44,7 @@ import org.elasticsearch.search.aggregations.LeafBucketCollectorBase;
 import org.elasticsearch.search.aggregations.bucket.terms.InternalTerms.Bucket;
 import org.elasticsearch.search.aggregations.bucket.terms.support.BucketPriorityQueue;
 import org.elasticsearch.search.aggregations.bucket.terms.support.IncludeExclude;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.aggregations.support.ValuesSource;
 
@@ -73,8 +73,11 @@ public class GlobalOrdinalsStringTermsAggregator extends AbstractStringTermsAggr
 
     public GlobalOrdinalsStringTermsAggregator(String name, AggregatorFactories factories, ValuesSource.Bytes.WithOrdinals valuesSource,
                                                Terms.Order order, BucketCountThresholds bucketCountThresholds,
-                                               IncludeExclude.OrdinalsFilter includeExclude, AggregationContext aggregationContext, Aggregator parent, SubAggCollectionMode collectionMode, boolean showTermDocCountError, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+ IncludeExclude.OrdinalsFilter includeExclude,
-        super(name, factories, aggregationContext, parent, order, bucketCountThresholds, collectionMode, showTermDocCountError, reducers,
+            AggregationContext aggregationContext, Aggregator parent, SubAggCollectionMode collectionMode, boolean showTermDocCountError,
+            List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
+        super(name, factories, aggregationContext, parent, order, bucketCountThresholds, collectionMode, showTermDocCountError,
+                pipelineAggregators,
                 metaData);
         this.valuesSource = valuesSource;
         this.includeExclude = includeExclude;
@@ -200,7 +203,7 @@ public class GlobalOrdinalsStringTermsAggregator extends AbstractStringTermsAggr
         }
 
         return new StringTerms(name, order, bucketCountThresholds.getRequiredSize(), bucketCountThresholds.getShardSize(),
-                bucketCountThresholds.getMinDocCount(), Arrays.asList(list), showTermDocCountError, 0, otherDocCount, reducers(),
+                bucketCountThresholds.getMinDocCount(), Arrays.asList(list), showTermDocCountError, 0, otherDocCount, pipelineAggregators(),
                 metaData());
     }
 
@@ -266,8 +269,11 @@ public class GlobalOrdinalsStringTermsAggregator extends AbstractStringTermsAggr
 
         public WithHash(String name, AggregatorFactories factories, ValuesSource.Bytes.WithOrdinals.FieldData valuesSource,
                         Terms.Order order, BucketCountThresholds bucketCountThresholds, IncludeExclude.OrdinalsFilter includeExclude, AggregationContext aggregationContext,
-                        Aggregator parent, SubAggCollectionMode collectionMode, boolean showTermDocCountError, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+ Aggregator parent, SubAggCollectionMode collectionMode,
-            super(name, factories, valuesSource, order, bucketCountThresholds, includeExclude, aggregationContext, parent, collectionMode, showTermDocCountError, reducers, metaData);
+                boolean showTermDocCountError, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData)
+                throws IOException {
+            super(name, factories, valuesSource, order, bucketCountThresholds, includeExclude, aggregationContext, parent, collectionMode,
+                    showTermDocCountError, pipelineAggregators, metaData);
             bucketOrds = new LongHash(1, aggregationContext.bigArrays());
         }
 
@@ -335,8 +341,12 @@ public class GlobalOrdinalsStringTermsAggregator extends AbstractStringTermsAggr
         private RandomAccessOrds segmentOrds;
 
         public LowCardinality(String name, AggregatorFactories factories, ValuesSource.Bytes.WithOrdinals valuesSource,
-                              Terms.Order order, BucketCountThresholds bucketCountThresholds, AggregationContext aggregationContext, Aggregator parent, SubAggCollectionMode collectionMode, boolean showTermDocCountError, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+ Terms.Order order,
-            super(name, factories, valuesSource, order, bucketCountThresholds, null, aggregationContext, parent, collectionMode, showTermDocCountError, reducers, metaData);
+                BucketCountThresholds bucketCountThresholds, AggregationContext aggregationContext, Aggregator parent,
+                SubAggCollectionMode collectionMode, boolean showTermDocCountError, List<PipelineAggregator> pipelineAggregators,
+                Map<String, Object> metaData) throws IOException {
+            super(name, factories, valuesSource, order, bucketCountThresholds, null, aggregationContext, parent, collectionMode,
+                    showTermDocCountError, pipelineAggregators, metaData);
             assert factories == null || factories.count() == 0;
             this.segmentDocCounts = context.bigArrays().newIntArray(1, true);
         }

src/main/java/org/elasticsearch/search/aggregations/bucket/terms/InternalTerms.java

@@ -30,7 +30,7 @@ import org.elasticsearch.search.aggregations.InternalAggregation;
 import org.elasticsearch.search.aggregations.InternalAggregations;
 import org.elasticsearch.search.aggregations.InternalMultiBucketAggregation;
 import org.elasticsearch.search.aggregations.bucket.terms.support.BucketPriorityQueue;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.format.ValueFormatter;
 
 import java.util.ArrayList;
@@ -124,9 +124,9 @@ public abstract class InternalTerms<A extends InternalTerms, B extends InternalT
     protected InternalTerms() {} // for serialization
 
     protected InternalTerms(String name, Terms.Order order, int requiredSize, int shardSize, long minDocCount,
-            List<? extends Bucket> buckets, boolean showTermDocCountError, long docCountError, long otherDocCount, List<Reducer> reducers,
+            List<? extends Bucket> buckets, boolean showTermDocCountError, long docCountError, long otherDocCount, List<PipelineAggregator> pipelineAggregators,
             Map<String, Object> metaData) {
-        super(name, reducers, metaData);
+        super(name, pipelineAggregators, metaData);
         this.order = order;
         this.requiredSize = requiredSize;
         this.shardSize = shardSize;

src/main/java/org/elasticsearch/search/aggregations/bucket/terms/LongTerms.java

@@ -26,7 +26,7 @@ import org.elasticsearch.search.aggregations.AggregationStreams;
 import org.elasticsearch.search.aggregations.InternalAggregations;
 import org.elasticsearch.search.aggregations.bucket.BucketStreamContext;
 import org.elasticsearch.search.aggregations.bucket.BucketStreams;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.format.ValueFormatter;
 import org.elasticsearch.search.aggregations.support.format.ValueFormatterStreams;
 
@@ -158,8 +158,8 @@ public class LongTerms extends InternalTerms<LongTerms, LongTerms.Bucket> {
 
     public LongTerms(String name, Terms.Order order, @Nullable ValueFormatter formatter, int requiredSize, int shardSize, long minDocCount,
             List<? extends InternalTerms.Bucket> buckets, boolean showTermDocCountError, long docCountError, long otherDocCount,
-            List<Reducer> reducers, Map<String, Object> metaData) {
+            List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
-        super(name, order, requiredSize, shardSize, minDocCount, buckets, showTermDocCountError, docCountError, otherDocCount, reducers,
+        super(name, order, requiredSize, shardSize, minDocCount, buckets, showTermDocCountError, docCountError, otherDocCount, pipelineAggregators,
                 metaData);
         this.formatter = formatter;
     }
@@ -172,7 +172,7 @@ public class LongTerms extends InternalTerms<LongTerms, LongTerms.Bucket> {
     @Override
     public LongTerms create(List<Bucket> buckets) {
         return new LongTerms(this.name, this.order, this.formatter, this.requiredSize, this.shardSize, this.minDocCount, buckets,
-                this.showTermDocCountError, this.docCountError, this.otherDocCount, this.reducers(), this.metaData);
+                this.showTermDocCountError, this.docCountError, this.otherDocCount, this.pipelineAggregators(), this.metaData);
     }
 
     @Override
@@ -185,7 +185,7 @@ public class LongTerms extends InternalTerms<LongTerms, LongTerms.Bucket> {
     protected LongTerms create(String name, List<org.elasticsearch.search.aggregations.bucket.terms.InternalTerms.Bucket> buckets,
             long docCountError, long otherDocCount, InternalTerms prototype) {
         return new LongTerms(name, prototype.order, ((LongTerms) prototype).formatter, prototype.requiredSize, prototype.shardSize,
-                prototype.minDocCount, buckets, prototype.showTermDocCountError, docCountError, otherDocCount, prototype.reducers(),
+                prototype.minDocCount, buckets, prototype.showTermDocCountError, docCountError, otherDocCount, prototype.pipelineAggregators(),
                 prototype.getMetaData());
     }
 

src/main/java/org/elasticsearch/search/aggregations/bucket/terms/LongTermsAggregator.java

@@ -31,7 +31,7 @@ import org.elasticsearch.search.aggregations.LeafBucketCollector;
 import org.elasticsearch.search.aggregations.bucket.terms.support.BucketPriorityQueue;
 import org.elasticsearch.search.aggregations.bucket.terms.support.IncludeExclude;
 import org.elasticsearch.search.aggregations.bucket.terms.support.IncludeExclude.LongFilter;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.aggregations.support.ValuesSource;
 import org.elasticsearch.search.aggregations.support.format.ValueFormat;
@@ -57,8 +57,8 @@ public class LongTermsAggregator extends TermsAggregator {
     public LongTermsAggregator(String name, AggregatorFactories factories, ValuesSource.Numeric valuesSource, @Nullable ValueFormat format,
             Terms.Order order, BucketCountThresholds bucketCountThresholds, AggregationContext aggregationContext, Aggregator parent,
             SubAggCollectionMode subAggCollectMode, boolean showTermDocCountError, IncludeExclude.LongFilter longFilter,
-            List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+            List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
-        super(name, factories, aggregationContext, parent, bucketCountThresholds, order, subAggCollectMode, reducers, metaData);
+        super(name, factories, aggregationContext, parent, bucketCountThresholds, order, subAggCollectMode, pipelineAggregators, metaData);
         this.valuesSource = valuesSource;
         this.showTermDocCountError = showTermDocCountError;
         this.formatter = format != null ? format.formatter() : null;
@@ -162,7 +162,7 @@ public class LongTermsAggregator extends TermsAggregator {
         }
 
         return new LongTerms(name, order, formatter, bucketCountThresholds.getRequiredSize(), bucketCountThresholds.getShardSize(),
-                bucketCountThresholds.getMinDocCount(), Arrays.asList(list), showTermDocCountError, 0, otherDocCount, reducers(),
+                bucketCountThresholds.getMinDocCount(), Arrays.asList(list), showTermDocCountError, 0, otherDocCount, pipelineAggregators(),
                 metaData());
     }
 
@@ -170,7 +170,7 @@ public class LongTermsAggregator extends TermsAggregator {
     public InternalAggregation buildEmptyAggregation() {
         return new LongTerms(name, order, formatter, bucketCountThresholds.getRequiredSize(), bucketCountThresholds.getShardSize(),
                 bucketCountThresholds.getMinDocCount(), Collections.<InternalTerms.Bucket> emptyList(), showTermDocCountError, 0, 0,
-                reducers(), metaData());
+                pipelineAggregators(), metaData());
     }
 
     @Override

src/main/java/org/elasticsearch/search/aggregations/bucket/terms/StringTerms.java

@@ -27,7 +27,7 @@ import org.elasticsearch.search.aggregations.InternalAggregation;
 import org.elasticsearch.search.aggregations.InternalAggregations;
 import org.elasticsearch.search.aggregations.bucket.BucketStreamContext;
 import org.elasticsearch.search.aggregations.bucket.BucketStreams;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -153,8 +153,8 @@ public class StringTerms extends InternalTerms<StringTerms, StringTerms.Bucket>
 
     public StringTerms(String name, Terms.Order order, int requiredSize, int shardSize, long minDocCount,
             List<? extends InternalTerms.Bucket> buckets, boolean showTermDocCountError, long docCountError, long otherDocCount,
-            List<Reducer> reducers, Map<String, Object> metaData) {
+            List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
-        super(name, order, requiredSize, shardSize, minDocCount, buckets, showTermDocCountError, docCountError, otherDocCount, reducers,
+        super(name, order, requiredSize, shardSize, minDocCount, buckets, showTermDocCountError, docCountError, otherDocCount, pipelineAggregators,
                 metaData);
     }
 
@@ -166,7 +166,7 @@ public class StringTerms extends InternalTerms<StringTerms, StringTerms.Bucket>
     @Override
     public StringTerms create(List<Bucket> buckets) {
         return new StringTerms(this.name, this.order, this.requiredSize, this.shardSize, this.minDocCount, buckets,
-                this.showTermDocCountError, this.docCountError, this.otherDocCount, this.reducers(), this.metaData);
+                this.showTermDocCountError, this.docCountError, this.otherDocCount, this.pipelineAggregators(), this.metaData);
     }
 
     @Override
@@ -178,7 +178,7 @@ public class StringTerms extends InternalTerms<StringTerms, StringTerms.Bucket>
     protected StringTerms create(String name, List<org.elasticsearch.search.aggregations.bucket.terms.InternalTerms.Bucket> buckets,
             long docCountError, long otherDocCount, InternalTerms prototype) {
         return new StringTerms(name, prototype.order, prototype.requiredSize, prototype.shardSize, prototype.minDocCount, buckets,
-                prototype.showTermDocCountError, docCountError, otherDocCount, prototype.reducers(), prototype.getMetaData());
+                prototype.showTermDocCountError, docCountError, otherDocCount, prototype.pipelineAggregators(), prototype.getMetaData());
     }
 
     @Override

src/main/java/org/elasticsearch/search/aggregations/bucket/terms/StringTermsAggregator.java

@@ -31,7 +31,7 @@ import org.elasticsearch.search.aggregations.InternalAggregation;
 import org.elasticsearch.search.aggregations.LeafBucketCollector;
 import org.elasticsearch.search.aggregations.bucket.terms.support.BucketPriorityQueue;
 import org.elasticsearch.search.aggregations.bucket.terms.support.IncludeExclude;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.aggregations.support.ValuesSource;
 
@@ -52,10 +52,10 @@ public class StringTermsAggregator extends AbstractStringTermsAggregator {
     public StringTermsAggregator(String name, AggregatorFactories factories, ValuesSource valuesSource,
             Terms.Order order, BucketCountThresholds bucketCountThresholds,
             IncludeExclude.StringFilter includeExclude, AggregationContext aggregationContext,
-            Aggregator parent, SubAggCollectionMode collectionMode, boolean showTermDocCountError, List<Reducer> reducers,
+            Aggregator parent, SubAggCollectionMode collectionMode, boolean showTermDocCountError, List<PipelineAggregator> pipelineAggregators,
             Map<String, Object> metaData) throws IOException {
 
-        super(name, factories, aggregationContext, parent, order, bucketCountThresholds, collectionMode, showTermDocCountError, reducers,
+        super(name, factories, aggregationContext, parent, order, bucketCountThresholds, collectionMode, showTermDocCountError, pipelineAggregators,
                 metaData);
         this.valuesSource = valuesSource;
         this.includeExclude = includeExclude;
@@ -164,7 +164,7 @@ public class StringTermsAggregator extends AbstractStringTermsAggregator {
         }
         
         return new StringTerms(name, order, bucketCountThresholds.getRequiredSize(), bucketCountThresholds.getShardSize(),
-                bucketCountThresholds.getMinDocCount(), Arrays.asList(list), showTermDocCountError, 0, otherDocCount, reducers(),
+                bucketCountThresholds.getMinDocCount(), Arrays.asList(list), showTermDocCountError, 0, otherDocCount, pipelineAggregators(),
                 metaData());
     }
 

src/main/java/org/elasticsearch/search/aggregations/bucket/terms/TermsAggregator.java

@@ -28,7 +28,7 @@ import org.elasticsearch.search.aggregations.AggregatorFactories;
 import org.elasticsearch.search.aggregations.bucket.BucketsAggregator;
 import org.elasticsearch.search.aggregations.bucket.terms.InternalOrder.Aggregation;
 import org.elasticsearch.search.aggregations.bucket.terms.InternalOrder.CompoundOrder;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.aggregations.support.AggregationPath;
 
@@ -137,8 +137,8 @@ public abstract class TermsAggregator extends BucketsAggregator {
     protected final Set<Aggregator> aggsUsedForSorting = new HashSet<>();
     protected final SubAggCollectionMode collectMode;
 
-    public TermsAggregator(String name, AggregatorFactories factories, AggregationContext context, Aggregator parent, BucketCountThresholds bucketCountThresholds, Terms.Order order, SubAggCollectionMode collectMode, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+    public TermsAggregator(String name, AggregatorFactories factories, AggregationContext context, Aggregator parent, BucketCountThresholds bucketCountThresholds, Terms.Order order, SubAggCollectionMode collectMode, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
-        super(name, factories, context, parent, reducers, metaData);
+        super(name, factories, context, parent, pipelineAggregators, metaData);
         this.bucketCountThresholds = bucketCountThresholds;
         this.order = InternalOrder.validate(order, this);
         this.collectMode = collectMode;

src/main/java/org/elasticsearch/search/aggregations/bucket/terms/TermsAggregatorFactory.java

@@ -27,7 +27,7 @@ import org.elasticsearch.search.aggregations.AggregatorFactories;
 import org.elasticsearch.search.aggregations.InternalAggregation;
 import org.elasticsearch.search.aggregations.NonCollectingAggregator;
 import org.elasticsearch.search.aggregations.bucket.terms.support.IncludeExclude;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.aggregations.support.ValuesSource;
 import org.elasticsearch.search.aggregations.support.ValuesSourceAggregatorFactory;
@@ -40,20 +40,21 @@ import java.util.Map;
 /**
  *
  */
-public class TermsAggregatorFactory extends ValuesSourceAggregatorFactory<ValuesSource>  {
+public class TermsAggregatorFactory extends ValuesSourceAggregatorFactory<ValuesSource> {
 
     public enum ExecutionMode {
 
         MAP(new ParseField("map")) {
 
             @Override
-            Aggregator create(String name, AggregatorFactories factories, ValuesSource valuesSource,
+            Aggregator create(String name, AggregatorFactories factories, ValuesSource valuesSource, Terms.Order order,
-                              Terms.Order order, TermsAggregator.BucketCountThresholds bucketCountThresholds, IncludeExclude includeExclude,
+                    TermsAggregator.BucketCountThresholds bucketCountThresholds, IncludeExclude includeExclude,
                     AggregationContext aggregationContext, Aggregator parent, SubAggCollectionMode subAggCollectMode,
-                    boolean showTermDocCountError, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+                    boolean showTermDocCountError, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData)
+                    throws IOException {
                 final IncludeExclude.StringFilter filter = includeExclude == null ? null : includeExclude.convertToStringFilter();
-                return new StringTermsAggregator(name, factories, valuesSource, order, bucketCountThresholds, filter,
+                return new StringTermsAggregator(name, factories, valuesSource, order, bucketCountThresholds, filter, aggregationContext,
-                        aggregationContext, parent, subAggCollectMode, showTermDocCountError, reducers, metaData);
+                        parent, subAggCollectMode, showTermDocCountError, pipelineAggregators, metaData);
             }
 
             @Override
@@ -65,11 +66,15 @@ public class TermsAggregatorFactory extends ValuesSourceAggregatorFactory<Values
         GLOBAL_ORDINALS(new ParseField("global_ordinals")) {
 
             @Override
-            Aggregator create(String name, AggregatorFactories factories, ValuesSource valuesSource,
+            Aggregator create(String name, AggregatorFactories factories, ValuesSource valuesSource, Terms.Order order,
-                              Terms.Order order, TermsAggregator.BucketCountThresholds bucketCountThresholds, IncludeExclude includeExclude,
+                    TermsAggregator.BucketCountThresholds bucketCountThresholds, IncludeExclude includeExclude,
-                              AggregationContext aggregationContext, Aggregator parent, SubAggCollectionMode subAggCollectMode, boolean showTermDocCountError, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+                    AggregationContext aggregationContext, Aggregator parent, SubAggCollectionMode subAggCollectMode,
+                    boolean showTermDocCountError, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData)
+                    throws IOException {
                 final IncludeExclude.OrdinalsFilter filter = includeExclude == null ? null : includeExclude.convertToOrdinalsFilter();
-                return new GlobalOrdinalsStringTermsAggregator(name, factories, (ValuesSource.Bytes.WithOrdinals) valuesSource, order, bucketCountThresholds, filter, aggregationContext, parent, subAggCollectMode, showTermDocCountError, reducers, metaData);
+                return new GlobalOrdinalsStringTermsAggregator(name, factories, (ValuesSource.Bytes.WithOrdinals) valuesSource, order,
+                        bucketCountThresholds, filter, aggregationContext, parent, subAggCollectMode, showTermDocCountError,
+                        pipelineAggregators, metaData);
             }
 
             @Override
@@ -81,11 +86,15 @@ public class TermsAggregatorFactory extends ValuesSourceAggregatorFactory<Values
         GLOBAL_ORDINALS_HASH(new ParseField("global_ordinals_hash")) {
 
             @Override
-            Aggregator create(String name, AggregatorFactories factories, ValuesSource valuesSource,
+            Aggregator create(String name, AggregatorFactories factories, ValuesSource valuesSource, Terms.Order order,
-                              Terms.Order order, TermsAggregator.BucketCountThresholds bucketCountThresholds, IncludeExclude includeExclude,
+                    TermsAggregator.BucketCountThresholds bucketCountThresholds, IncludeExclude includeExclude,
-                              AggregationContext aggregationContext, Aggregator parent, SubAggCollectionMode subAggCollectMode, boolean showTermDocCountError, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+                    AggregationContext aggregationContext, Aggregator parent, SubAggCollectionMode subAggCollectMode,
+                    boolean showTermDocCountError, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData)
+                    throws IOException {
                 final IncludeExclude.OrdinalsFilter filter = includeExclude == null ? null : includeExclude.convertToOrdinalsFilter();
-                return new GlobalOrdinalsStringTermsAggregator.WithHash(name, factories, (ValuesSource.Bytes.WithOrdinals.FieldData) valuesSource, order, bucketCountThresholds, filter, aggregationContext, parent, subAggCollectMode, showTermDocCountError, reducers, metaData);
+                return new GlobalOrdinalsStringTermsAggregator.WithHash(name, factories,
+                        (ValuesSource.Bytes.WithOrdinals.FieldData) valuesSource, order, bucketCountThresholds, filter, aggregationContext,
+                        parent, subAggCollectMode, showTermDocCountError, pipelineAggregators, metaData);
             }
 
             @Override
@@ -96,14 +105,18 @@ public class TermsAggregatorFactory extends ValuesSourceAggregatorFactory<Values
         GLOBAL_ORDINALS_LOW_CARDINALITY(new ParseField("global_ordinals_low_cardinality")) {
 
             @Override
-            Aggregator create(String name, AggregatorFactories factories, ValuesSource valuesSource,
+            Aggregator create(String name, AggregatorFactories factories, ValuesSource valuesSource, Terms.Order order,
-                              Terms.Order order, TermsAggregator.BucketCountThresholds bucketCountThresholds, IncludeExclude includeExclude,
+                    TermsAggregator.BucketCountThresholds bucketCountThresholds, IncludeExclude includeExclude,
                     AggregationContext aggregationContext, Aggregator parent, SubAggCollectionMode subAggCollectMode,
-                    boolean showTermDocCountError, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+                    boolean showTermDocCountError, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData)
+                    throws IOException {
                 if (includeExclude != null || factories.count() > 0) {
-                    return GLOBAL_ORDINALS.create(name, factories, valuesSource, order, bucketCountThresholds, includeExclude, aggregationContext, parent, subAggCollectMode, showTermDocCountError, reducers, metaData);
+                    return GLOBAL_ORDINALS.create(name, factories, valuesSource, order, bucketCountThresholds, includeExclude,
+                            aggregationContext, parent, subAggCollectMode, showTermDocCountError, pipelineAggregators, metaData);
                 }
-                return new GlobalOrdinalsStringTermsAggregator.LowCardinality(name, factories, (ValuesSource.Bytes.WithOrdinals) valuesSource, order, bucketCountThresholds, aggregationContext, parent, subAggCollectMode, showTermDocCountError, reducers, metaData);
+                return new GlobalOrdinalsStringTermsAggregator.LowCardinality(name, factories,
+                        (ValuesSource.Bytes.WithOrdinals) valuesSource, order, bucketCountThresholds, aggregationContext, parent,
+                        subAggCollectMode, showTermDocCountError, pipelineAggregators, metaData);
             }
 
             @Override
@@ -127,10 +140,11 @@ public class TermsAggregatorFactory extends ValuesSourceAggregatorFactory<Values
             this.parseField = parseField;
         }
 
-        abstract Aggregator create(String name, AggregatorFactories factories, ValuesSource valuesSource,
+        abstract Aggregator create(String name, AggregatorFactories factories, ValuesSource valuesSource, Terms.Order order,
-                                   Terms.Order order, TermsAggregator.BucketCountThresholds bucketCountThresholds,
+                TermsAggregator.BucketCountThresholds bucketCountThresholds, IncludeExclude includeExclude,
-                                   IncludeExclude includeExclude, AggregationContext aggregationContext, Aggregator parent,
+                AggregationContext aggregationContext, Aggregator parent, SubAggCollectionMode subAggCollectMode,
-                                   SubAggCollectionMode subAggCollectMode, boolean showTermDocCountError, List<Reducer> reducers, Map<String, Object> metaData) throws IOException;
+                boolean showTermDocCountError, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData)
+                throws IOException;
 
         abstract boolean needsGlobalOrdinals();
 
@@ -147,7 +161,9 @@ public class TermsAggregatorFactory extends ValuesSourceAggregatorFactory<Values
     private final TermsAggregator.BucketCountThresholds bucketCountThresholds;
     private final boolean showTermDocCountError;
 
-    public TermsAggregatorFactory(String name, ValuesSourceConfig config, Terms.Order order, TermsAggregator.BucketCountThresholds bucketCountThresholds, IncludeExclude includeExclude, String executionHint, SubAggCollectionMode executionMode, boolean showTermDocCountError) {
+    public TermsAggregatorFactory(String name, ValuesSourceConfig config, Terms.Order order,
+            TermsAggregator.BucketCountThresholds bucketCountThresholds, IncludeExclude includeExclude, String executionHint,
+            SubAggCollectionMode executionMode, boolean showTermDocCountError) {
         super(name, StringTerms.TYPE.name(), config);
         this.order = order;
         this.includeExclude = includeExclude;
@@ -158,15 +174,16 @@ public class TermsAggregatorFactory extends ValuesSourceAggregatorFactory<Values
     }
 
     @Override
-    protected Aggregator createUnmapped(AggregationContext aggregationContext, Aggregator parent, List<Reducer> reducers,
+    protected Aggregator createUnmapped(AggregationContext aggregationContext, Aggregator parent,
-            Map<String, Object> metaData) throws IOException {
+            List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
         final InternalAggregation aggregation = new UnmappedTerms(name, order, bucketCountThresholds.getRequiredSize(),
-                bucketCountThresholds.getShardSize(), bucketCountThresholds.getMinDocCount(), reducers, metaData);
+                bucketCountThresholds.getShardSize(), bucketCountThresholds.getMinDocCount(), pipelineAggregators, metaData);
-        return new NonCollectingAggregator(name, aggregationContext, parent, factories, reducers, metaData) {
+        return new NonCollectingAggregator(name, aggregationContext, parent, factories, pipelineAggregators, metaData) {
             {
                 // even in the case of an unmapped aggregator, validate the order
                 InternalOrder.validate(order, this);
             }
+
             @Override
             public InternalAggregation buildEmptyAggregation() {
                 return aggregation;
@@ -176,7 +193,8 @@ public class TermsAggregatorFactory extends ValuesSourceAggregatorFactory<Values
 
     @Override
     protected Aggregator doCreateInternal(ValuesSource valuesSource, AggregationContext aggregationContext, Aggregator parent,
-            boolean collectsFromSingleBucket, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+            boolean collectsFromSingleBucket, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData)
+            throws IOException {
         if (collectsFromSingleBucket == false) {
             return asMultiBucketAggregator(this, aggregationContext, parent);
         }
@@ -226,12 +244,16 @@ public class TermsAggregatorFactory extends ValuesSourceAggregatorFactory<Values
             }
 
             assert execution != null;
-            return execution.create(name, factories, valuesSource, order, bucketCountThresholds, includeExclude, aggregationContext, parent, collectMode, showTermDocCountError, reducers, metaData);
+            return execution.create(name, factories, valuesSource, order, bucketCountThresholds, includeExclude, aggregationContext,
+                    parent, collectMode, showTermDocCountError, pipelineAggregators, metaData);
         }
 
         if ((includeExclude != null) && (includeExclude.isRegexBased())) {
-            throw new AggregationExecutionException("Aggregation [" + name + "] cannot support regular expression style include/exclude " +
+            throw new AggregationExecutionException(
-                    "settings as they can only be applied to string fields. Use an array of numeric values for include/exclude clauses used to filter numeric fields");
+                    "Aggregation ["
+                            + name
+                            + "] cannot support regular expression style include/exclude "
+                            + "settings as they can only be applied to string fields. Use an array of numeric values for include/exclude clauses used to filter numeric fields");
         }
 
         if (valuesSource instanceof ValuesSource.Numeric) {
@@ -240,19 +262,20 @@ public class TermsAggregatorFactory extends ValuesSourceAggregatorFactory<Values
                 if (includeExclude != null) {
                     longFilter = includeExclude.convertToDoubleFilter();
                 }
-                return new DoubleTermsAggregator(name, factories, (ValuesSource.Numeric) valuesSource, config.format(),
+                return new DoubleTermsAggregator(name, factories, (ValuesSource.Numeric) valuesSource, config.format(), order,
-                        order, bucketCountThresholds, aggregationContext, parent, collectMode,
+                        bucketCountThresholds, aggregationContext, parent, collectMode, showTermDocCountError, longFilter,
-                        showTermDocCountError, longFilter, reducers, metaData);
+                        pipelineAggregators, metaData);
             }
             if (includeExclude != null) {
                 longFilter = includeExclude.convertToLongFilter();
             }
-            return new LongTermsAggregator(name, factories, (ValuesSource.Numeric) valuesSource, config.format(),
+            return new LongTermsAggregator(name, factories, (ValuesSource.Numeric) valuesSource, config.format(), order,
-                    order, bucketCountThresholds, aggregationContext, parent, collectMode, showTermDocCountError, longFilter, reducers, metaData);
+                    bucketCountThresholds, aggregationContext, parent, collectMode, showTermDocCountError, longFilter, pipelineAggregators,
+                    metaData);
         }
 
-        throw new AggregationExecutionException("terms aggregation cannot be applied to field [" + config.fieldContext().field() +
+        throw new AggregationExecutionException("terms aggregation cannot be applied to field [" + config.fieldContext().field()
-                "]. It can only be applied to numeric or string fields.");
+                + "]. It can only be applied to numeric or string fields.");
     }
 
 }

src/main/java/org/elasticsearch/search/aggregations/bucket/terms/UnmappedTerms.java

@@ -24,7 +24,7 @@ import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.search.aggregations.AggregationStreams;
 import org.elasticsearch.search.aggregations.InternalAggregation;
 import org.elasticsearch.search.aggregations.InternalAggregations;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -56,9 +56,9 @@ public class UnmappedTerms extends InternalTerms<UnmappedTerms, InternalTerms.Bu
 
     UnmappedTerms() {} // for serialization
 
-    public UnmappedTerms(String name, Terms.Order order, int requiredSize, int shardSize, long minDocCount, List<Reducer> reducers,
+    public UnmappedTerms(String name, Terms.Order order, int requiredSize, int shardSize, long minDocCount, List<PipelineAggregator> pipelineAggregators,
             Map<String, Object> metaData) {
-        super(name, order, requiredSize, shardSize, minDocCount, BUCKETS, false, 0, 0, reducers, metaData);
+        super(name, order, requiredSize, shardSize, minDocCount, BUCKETS, false, 0, 0, pipelineAggregators, metaData);
     }
 
     @Override
@@ -68,7 +68,7 @@ public class UnmappedTerms extends InternalTerms<UnmappedTerms, InternalTerms.Bu
 
     @Override
     public UnmappedTerms create(List<InternalTerms.Bucket> buckets) {
-        return new UnmappedTerms(this.name, this.order, this.requiredSize, this.shardSize, this.minDocCount, this.reducers(), this.metaData);
+        return new UnmappedTerms(this.name, this.order, this.requiredSize, this.shardSize, this.minDocCount, this.pipelineAggregators(), this.metaData);
     }
 
     @Override

src/main/java/org/elasticsearch/search/aggregations/metrics/InternalMetricsAggregation.java

@@ -20,7 +20,7 @@
 package org.elasticsearch.search.aggregations.metrics;
 
 import org.elasticsearch.search.aggregations.InternalAggregation;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 
 import java.util.List;
 import java.util.Map;
@@ -29,7 +29,7 @@ public abstract class InternalMetricsAggregation extends InternalAggregation {
 
     protected InternalMetricsAggregation() {} // for serialization
 
-    protected InternalMetricsAggregation(String name, List<Reducer> reducers, Map<String, Object> metaData) {
+    protected InternalMetricsAggregation(String name, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
-        super(name, reducers, metaData);
+        super(name, pipelineAggregators, metaData);
     }
 }

src/main/java/org/elasticsearch/search/aggregations/metrics/InternalNumericMetricsAggregation.java

@@ -18,7 +18,7 @@
  */
 package org.elasticsearch.search.aggregations.metrics;
 
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.format.ValueFormatter;
 
 import java.util.List;
@@ -35,8 +35,8 @@ public abstract class InternalNumericMetricsAggregation extends InternalMetricsA
 
         protected SingleValue() {}
 
-        protected SingleValue(String name, List<Reducer> reducers, Map<String, Object> metaData) {
+        protected SingleValue(String name, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
-            super(name, reducers, metaData);
+            super(name, pipelineAggregators, metaData);
         }
 
         @Override
@@ -65,8 +65,8 @@ public abstract class InternalNumericMetricsAggregation extends InternalMetricsA
 
         protected MultiValue() {}
 
-        protected MultiValue(String name, List<Reducer> reducers, Map<String, Object> metaData) {
+        protected MultiValue(String name, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
-            super(name, reducers, metaData);
+            super(name, pipelineAggregators, metaData);
         }
 
         public abstract double value(String name);
@@ -93,8 +93,8 @@ public abstract class InternalNumericMetricsAggregation extends InternalMetricsA
 
     private InternalNumericMetricsAggregation() {} // for serialization
 
-    private InternalNumericMetricsAggregation(String name, List<Reducer> reducers, Map<String, Object> metaData) {
+    private InternalNumericMetricsAggregation(String name, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
-        super(name, reducers, metaData);
+        super(name, pipelineAggregators, metaData);
     }
 
 }

src/main/java/org/elasticsearch/search/aggregations/metrics/MetricsAggregator.java

@@ -22,7 +22,7 @@ package org.elasticsearch.search.aggregations.metrics;
 import org.elasticsearch.search.aggregations.Aggregator;
 import org.elasticsearch.search.aggregations.AggregatorBase;
 import org.elasticsearch.search.aggregations.AggregatorFactories;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 
 import java.io.IOException;
@@ -31,8 +31,8 @@ import java.util.Map;
 
 public abstract class MetricsAggregator extends AggregatorBase {
     
-    protected MetricsAggregator(String name, AggregationContext context, Aggregator parent, List<Reducer> reducers,
+    protected MetricsAggregator(String name, AggregationContext context, Aggregator parent, List<PipelineAggregator> pipelineAggregators,
             Map<String, Object> metaData) throws IOException {
-        super(name, AggregatorFactories.EMPTY, context, parent, reducers, metaData);
+        super(name, AggregatorFactories.EMPTY, context, parent, pipelineAggregators, metaData);
     }
 }

src/main/java/org/elasticsearch/search/aggregations/metrics/NumericMetricsAggregator.java

@@ -19,7 +19,7 @@
 package org.elasticsearch.search.aggregations.metrics;
 
 import org.elasticsearch.search.aggregations.Aggregator;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 
 import java.io.IOException;
@@ -31,16 +31,16 @@ import java.util.Map;
  */
 public abstract class NumericMetricsAggregator extends MetricsAggregator {
 
-    private NumericMetricsAggregator(String name, AggregationContext context, Aggregator parent, List<Reducer> reducers,
+    private NumericMetricsAggregator(String name, AggregationContext context, Aggregator parent,
-            Map<String, Object> metaData) throws IOException {
+            List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
-        super(name, context, parent, reducers, metaData);
+        super(name, context, parent, pipelineAggregators, metaData);
     }
 
     public static abstract class SingleValue extends NumericMetricsAggregator {
 
-        protected SingleValue(String name, AggregationContext context, Aggregator parent, List<Reducer> reducers,
+        protected SingleValue(String name, AggregationContext context, Aggregator parent, List<PipelineAggregator> pipelineAggregators,
                 Map<String, Object> metaData) throws IOException {
-            super(name, context, parent, reducers, metaData);
+            super(name, context, parent, pipelineAggregators, metaData);
         }
 
         public abstract double metric(long owningBucketOrd);
@@ -48,9 +48,9 @@ public abstract class NumericMetricsAggregator extends MetricsAggregator {
 
     public static abstract class MultiValue extends NumericMetricsAggregator {
 
-        protected MultiValue(String name, AggregationContext context, Aggregator parent, List<Reducer> reducers,
+        protected MultiValue(String name, AggregationContext context, Aggregator parent, List<PipelineAggregator> pipelineAggregators,
                 Map<String, Object> metaData) throws IOException {
-            super(name, context, parent, reducers, metaData);
+            super(name, context, parent, pipelineAggregators, metaData);
         }
 
         public abstract boolean hasMetric(String name);

src/main/java/org/elasticsearch/search/aggregations/metrics/avg/AvgAggregator.java

@@ -30,7 +30,7 @@ import org.elasticsearch.search.aggregations.InternalAggregation;
 import org.elasticsearch.search.aggregations.LeafBucketCollector;
 import org.elasticsearch.search.aggregations.LeafBucketCollectorBase;
 import org.elasticsearch.search.aggregations.metrics.NumericMetricsAggregator;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.aggregations.support.ValuesSource;
 import org.elasticsearch.search.aggregations.support.ValuesSourceAggregatorFactory;
@@ -53,8 +53,9 @@ public class AvgAggregator extends NumericMetricsAggregator.SingleValue {
     ValueFormatter formatter;
 
     public AvgAggregator(String name, ValuesSource.Numeric valuesSource, @Nullable ValueFormatter formatter,
-            AggregationContext context, Aggregator parent, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+ AggregationContext context,
-        super(name, context, parent, reducers, metaData);
+            Aggregator parent, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
+        super(name, context, parent, pipelineAggregators, metaData);
         this.valuesSource = valuesSource;
         this.formatter = formatter;
         if (valuesSource != null) {
@@ -105,12 +106,12 @@ public class AvgAggregator extends NumericMetricsAggregator.SingleValue {
         if (valuesSource == null || bucket >= sums.size()) {
             return buildEmptyAggregation();
         }
-        return new InternalAvg(name, sums.get(bucket), counts.get(bucket), formatter, reducers(), metaData());
+        return new InternalAvg(name, sums.get(bucket), counts.get(bucket), formatter, pipelineAggregators(), metaData());
     }
 
     @Override
     public InternalAggregation buildEmptyAggregation() {
-        return new InternalAvg(name, 0.0, 0l, formatter, reducers(), metaData());
+        return new InternalAvg(name, 0.0, 0l, formatter, pipelineAggregators(), metaData());
     }
 
     public static class Factory extends ValuesSourceAggregatorFactory.LeafOnly<ValuesSource.Numeric> {
@@ -120,15 +121,17 @@ public class AvgAggregator extends NumericMetricsAggregator.SingleValue {
         }
 
         @Override
-        protected Aggregator createUnmapped(AggregationContext aggregationContext, Aggregator parent, List<Reducer> reducers,
+        protected Aggregator createUnmapped(AggregationContext aggregationContext, Aggregator parent,
+                List<PipelineAggregator> pipelineAggregators,
                 Map<String, Object> metaData) throws IOException {
-            return new AvgAggregator(name, null, config.formatter(), aggregationContext, parent, reducers, metaData);
+            return new AvgAggregator(name, null, config.formatter(), aggregationContext, parent, pipelineAggregators, metaData);
         }
 
         @Override
         protected Aggregator doCreateInternal(ValuesSource.Numeric valuesSource, AggregationContext aggregationContext, Aggregator parent,
-                boolean collectsFromSingleBucket, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+                boolean collectsFromSingleBucket, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData)
-            return new AvgAggregator(name, valuesSource, config.formatter(), aggregationContext, parent, reducers, metaData);
+                throws IOException {
+            return new AvgAggregator(name, valuesSource, config.formatter(), aggregationContext, parent, pipelineAggregators, metaData);
         }
     }
 

src/main/java/org/elasticsearch/search/aggregations/metrics/avg/InternalAvg.java

@@ -25,7 +25,7 @@ import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.search.aggregations.AggregationStreams;
 import org.elasticsearch.search.aggregations.InternalAggregation;
 import org.elasticsearch.search.aggregations.metrics.InternalNumericMetricsAggregation;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.format.ValueFormatter;
 import org.elasticsearch.search.aggregations.support.format.ValueFormatterStreams;
 
@@ -58,9 +58,9 @@ public class InternalAvg extends InternalNumericMetricsAggregation.SingleValue i
 
     InternalAvg() {} // for serialization
 
-    public InternalAvg(String name, double sum, long count, @Nullable ValueFormatter formatter, List<Reducer> reducers,
+    public InternalAvg(String name, double sum, long count, @Nullable ValueFormatter formatter, List<PipelineAggregator> pipelineAggregators,
             Map<String, Object> metaData) {
-        super(name, reducers, metaData);
+        super(name, pipelineAggregators, metaData);
         this.sum = sum;
         this.count = count;
         this.valueFormatter = formatter;
@@ -89,7 +89,7 @@ public class InternalAvg extends InternalNumericMetricsAggregation.SingleValue i
             count += ((InternalAvg) aggregation).count;
             sum += ((InternalAvg) aggregation).sum;
         }
-        return new InternalAvg(getName(), sum, count, valueFormatter, reducers(), getMetaData());
+        return new InternalAvg(getName(), sum, count, valueFormatter, pipelineAggregators(), getMetaData());
     }
 
     @Override

src/main/java/org/elasticsearch/search/aggregations/metrics/cardinality/CardinalityAggregator.java

@@ -42,7 +42,7 @@ import org.elasticsearch.search.aggregations.Aggregator;
 import org.elasticsearch.search.aggregations.InternalAggregation;
 import org.elasticsearch.search.aggregations.LeafBucketCollector;
 import org.elasticsearch.search.aggregations.metrics.NumericMetricsAggregator;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.aggregations.support.ValuesSource;
 import org.elasticsearch.search.aggregations.support.format.ValueFormatter;
@@ -68,8 +68,8 @@ public class CardinalityAggregator extends NumericMetricsAggregator.SingleValue
     private ValueFormatter formatter;
 
     public CardinalityAggregator(String name, ValuesSource valuesSource, boolean rehash, int precision, @Nullable ValueFormatter formatter,
-            AggregationContext context, Aggregator parent, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+            AggregationContext context, Aggregator parent, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
-        super(name, context, parent, reducers, metaData);
+        super(name, context, parent, pipelineAggregators, metaData);
         this.valuesSource = valuesSource;
         this.rehash = rehash;
         this.precision = precision;
@@ -158,12 +158,12 @@ public class CardinalityAggregator extends NumericMetricsAggregator.SingleValue
         // this Aggregator (and its HLL++ counters) is released.
         HyperLogLogPlusPlus copy = new HyperLogLogPlusPlus(precision, BigArrays.NON_RECYCLING_INSTANCE, 1);
         copy.merge(0, counts, owningBucketOrdinal);
-        return new InternalCardinality(name, copy, formatter, reducers(), metaData());
+        return new InternalCardinality(name, copy, formatter, pipelineAggregators(), metaData());
     }
 
     @Override
     public InternalAggregation buildEmptyAggregation() {
-        return new InternalCardinality(name, null, formatter, reducers(), metaData());
+        return new InternalCardinality(name, null, formatter, pipelineAggregators(), metaData());
     }
 
     @Override

src/main/java/org/elasticsearch/search/aggregations/metrics/cardinality/CardinalityAggregatorFactory.java

@@ -22,7 +22,7 @@ package org.elasticsearch.search.aggregations.metrics.cardinality;
 import org.elasticsearch.search.aggregations.AggregationExecutionException;
 import org.elasticsearch.search.aggregations.Aggregator;
 import org.elasticsearch.search.aggregations.bucket.SingleBucketAggregator;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.aggregations.support.ValuesSource;
 import org.elasticsearch.search.aggregations.support.ValuesSourceAggregatorFactory;
@@ -48,18 +48,18 @@ final class CardinalityAggregatorFactory extends ValuesSourceAggregatorFactory<V
     }
 
     @Override
-    protected Aggregator createUnmapped(AggregationContext context, Aggregator parent, List<Reducer> reducers, Map<String, Object> metaData)
+    protected Aggregator createUnmapped(AggregationContext context, Aggregator parent, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData)
             throws IOException {
-        return new CardinalityAggregator(name, null, true, precision(parent), config.formatter(), context, parent, reducers, metaData);
+        return new CardinalityAggregator(name, null, true, precision(parent), config.formatter(), context, parent, pipelineAggregators, metaData);
     }
 
     @Override
     protected Aggregator doCreateInternal(ValuesSource valuesSource, AggregationContext context, Aggregator parent,
-            boolean collectsFromSingleBucket, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+            boolean collectsFromSingleBucket, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
         if (!(valuesSource instanceof ValuesSource.Numeric) && !rehash) {
             throw new AggregationExecutionException("Turning off rehashing for cardinality aggregation [" + name + "] on non-numeric values in not allowed");
         }
-        return new CardinalityAggregator(name, valuesSource, rehash, precision(parent), config.formatter(), context, parent, reducers,
+        return new CardinalityAggregator(name, valuesSource, rehash, precision(parent), config.formatter(), context, parent, pipelineAggregators,
                 metaData);
     }
 

src/main/java/org/elasticsearch/search/aggregations/metrics/cardinality/InternalCardinality.java

@@ -27,7 +27,7 @@ import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.search.aggregations.AggregationStreams;
 import org.elasticsearch.search.aggregations.InternalAggregation;
 import org.elasticsearch.search.aggregations.metrics.InternalNumericMetricsAggregation;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.format.ValueFormatter;
 import org.elasticsearch.search.aggregations.support.format.ValueFormatterStreams;
 
@@ -54,9 +54,9 @@ public final class InternalCardinality extends InternalNumericMetricsAggregation
 
     private HyperLogLogPlusPlus counts;
 
-    InternalCardinality(String name, HyperLogLogPlusPlus counts, @Nullable ValueFormatter formatter, List<Reducer> reducers,
+    InternalCardinality(String name, HyperLogLogPlusPlus counts, @Nullable ValueFormatter formatter, List<PipelineAggregator> pipelineAggregators,
             Map<String, Object> metaData) {
-        super(name, reducers, metaData);
+        super(name, pipelineAggregators, metaData);
         this.counts = counts;
         this.valueFormatter = formatter;
     }
@@ -108,7 +108,7 @@ public final class InternalCardinality extends InternalNumericMetricsAggregation
             if (cardinality.counts != null) {
                 if (reduced == null) {
                     reduced = new InternalCardinality(name, new HyperLogLogPlusPlus(cardinality.counts.precision(),
-                            BigArrays.NON_RECYCLING_INSTANCE, 1), this.valueFormatter, reducers(), getMetaData());
+                            BigArrays.NON_RECYCLING_INSTANCE, 1), this.valueFormatter, pipelineAggregators(), getMetaData());
                 }
                 reduced.merge(cardinality);
             }

src/main/java/org/elasticsearch/search/aggregations/metrics/geobounds/GeoBoundsAggregator.java

@@ -30,7 +30,7 @@ import org.elasticsearch.search.aggregations.InternalAggregation;
 import org.elasticsearch.search.aggregations.LeafBucketCollector;
 import org.elasticsearch.search.aggregations.LeafBucketCollectorBase;
 import org.elasticsearch.search.aggregations.metrics.MetricsAggregator;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.aggregations.support.ValuesSource;
 import org.elasticsearch.search.aggregations.support.ValuesSourceAggregatorFactory;
@@ -52,9 +52,9 @@ public final class GeoBoundsAggregator extends MetricsAggregator {
     DoubleArray negRights;
 
     protected GeoBoundsAggregator(String name, AggregationContext aggregationContext, Aggregator parent,
-            ValuesSource.GeoPoint valuesSource, boolean wrapLongitude, List<Reducer> reducers,
+            ValuesSource.GeoPoint valuesSource, boolean wrapLongitude, List<PipelineAggregator> pipelineAggregators,
             Map<String, Object> metaData) throws IOException {
-        super(name, aggregationContext, parent, reducers, metaData);
+        super(name, aggregationContext, parent, pipelineAggregators, metaData);
         this.valuesSource = valuesSource;
         this.wrapLongitude = wrapLongitude;
         if (valuesSource != null) {
@@ -152,13 +152,13 @@ public final class GeoBoundsAggregator extends MetricsAggregator {
         double posRight = posRights.get(owningBucketOrdinal);
         double negLeft = negLefts.get(owningBucketOrdinal);
         double negRight = negRights.get(owningBucketOrdinal);
-        return new InternalGeoBounds(name, top, bottom, posLeft, posRight, negLeft, negRight, wrapLongitude, reducers(), metaData());
+        return new InternalGeoBounds(name, top, bottom, posLeft, posRight, negLeft, negRight, wrapLongitude, pipelineAggregators(), metaData());
     }
 
     @Override
     public InternalAggregation buildEmptyAggregation() {
         return new InternalGeoBounds(name, Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY, Double.POSITIVE_INFINITY,
-                Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY, Double.NEGATIVE_INFINITY, wrapLongitude, reducers(), metaData());
+                Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY, Double.NEGATIVE_INFINITY, wrapLongitude, pipelineAggregators(), metaData());
     }
     
     @Override
@@ -176,15 +176,16 @@ public final class GeoBoundsAggregator extends MetricsAggregator {
         }
 
         @Override
-        protected Aggregator createUnmapped(AggregationContext aggregationContext, Aggregator parent, List<Reducer> reducers,
+        protected Aggregator createUnmapped(AggregationContext aggregationContext, Aggregator parent,
-                Map<String, Object> metaData) throws IOException {
+                List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
-            return new GeoBoundsAggregator(name, aggregationContext, parent, null, wrapLongitude, reducers, metaData);
+            return new GeoBoundsAggregator(name, aggregationContext, parent, null, wrapLongitude, pipelineAggregators, metaData);
         }
 
         @Override
-        protected Aggregator doCreateInternal(ValuesSource.GeoPoint valuesSource, AggregationContext aggregationContext,
+        protected Aggregator doCreateInternal(ValuesSource.GeoPoint valuesSource, AggregationContext aggregationContext, Aggregator parent,
-                Aggregator parent, boolean collectsFromSingleBucket, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+                boolean collectsFromSingleBucket, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData)
-            return new GeoBoundsAggregator(name, aggregationContext, parent, valuesSource, wrapLongitude, reducers, metaData);
+                throws IOException {
+            return new GeoBoundsAggregator(name, aggregationContext, parent, valuesSource, wrapLongitude, pipelineAggregators, metaData);
         }
 
     }

src/main/java/org/elasticsearch/search/aggregations/metrics/geobounds/InternalGeoBounds.java

@@ -26,7 +26,7 @@ import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.search.aggregations.AggregationStreams;
 import org.elasticsearch.search.aggregations.InternalAggregation;
 import org.elasticsearch.search.aggregations.metrics.InternalMetricsAggregation;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 
 import java.io.IOException;
 import java.util.List;
@@ -57,8 +57,8 @@ public class InternalGeoBounds extends InternalMetricsAggregation implements Geo
     
     InternalGeoBounds(String name, double top, double bottom, double posLeft, double posRight,
             double negLeft, double negRight, boolean wrapLongitude,
-            List<Reducer> reducers, Map<String, Object> metaData) {
+            List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
-        super(name, reducers, metaData);
+        super(name, pipelineAggregators, metaData);
         this.top = top;
         this.bottom = bottom;
         this.posLeft = posLeft;
@@ -104,7 +104,7 @@ public class InternalGeoBounds extends InternalMetricsAggregation implements Geo
                 negRight = bounds.negRight;
             }
         }
-        return new InternalGeoBounds(name, top, bottom, posLeft, posRight, negLeft, negRight, wrapLongitude, reducers(), getMetaData());
+        return new InternalGeoBounds(name, top, bottom, posLeft, posRight, negLeft, negRight, wrapLongitude, pipelineAggregators(), getMetaData());
     }
 
     @Override

src/main/java/org/elasticsearch/search/aggregations/metrics/max/InternalMax.java

@@ -25,7 +25,7 @@ import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.search.aggregations.AggregationStreams;
 import org.elasticsearch.search.aggregations.InternalAggregation;
 import org.elasticsearch.search.aggregations.metrics.InternalNumericMetricsAggregation;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.format.ValueFormatter;
 import org.elasticsearch.search.aggregations.support.format.ValueFormatterStreams;
 
@@ -57,8 +57,8 @@ public class InternalMax extends InternalNumericMetricsAggregation.SingleValue i
 
     InternalMax() {} // for serialization
 
-    public InternalMax(String name, double max, @Nullable ValueFormatter formatter, List<Reducer> reducers, Map<String, Object> metaData) {
+    public InternalMax(String name, double max, @Nullable ValueFormatter formatter, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
-        super(name, reducers, metaData);
+        super(name, pipelineAggregators, metaData);
         this.valueFormatter = formatter;
         this.max = max;
     }
@@ -84,7 +84,7 @@ public class InternalMax extends InternalNumericMetricsAggregation.SingleValue i
         for (InternalAggregation aggregation : aggregations) {
             max = Math.max(max, ((InternalMax) aggregation).max);
         }
-        return new InternalMax(name, max, valueFormatter, reducers(), getMetaData());
+        return new InternalMax(name, max, valueFormatter, pipelineAggregators(), getMetaData());
     }
 
     @Override

src/main/java/org/elasticsearch/search/aggregations/metrics/max/MaxAggregator.java

@@ -31,7 +31,7 @@ import org.elasticsearch.search.aggregations.InternalAggregation;
 import org.elasticsearch.search.aggregations.LeafBucketCollector;
 import org.elasticsearch.search.aggregations.LeafBucketCollectorBase;
 import org.elasticsearch.search.aggregations.metrics.NumericMetricsAggregator;
-import org.elasticsearch.search.aggregations.reducers.Reducer;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
 import org.elasticsearch.search.aggregations.support.AggregationContext;
 import org.elasticsearch.search.aggregations.support.ValuesSource;
 import org.elasticsearch.search.aggregations.support.ValuesSourceAggregatorFactory;
@@ -53,9 +53,10 @@ public class MaxAggregator extends NumericMetricsAggregator.SingleValue {
     DoubleArray maxes;
 
     public MaxAggregator(String name, ValuesSource.Numeric valuesSource, @Nullable ValueFormatter formatter,
-            AggregationContext context, Aggregator parent, List<Reducer> reducers,
+ AggregationContext context,
+            Aggregator parent, List<PipelineAggregator> pipelineAggregators,
             Map<String, Object> metaData) throws IOException {
-        super(name, context, parent, reducers, metaData);
+        super(name, context, parent, pipelineAggregators, metaData);
         this.valuesSource = valuesSource;
         this.formatter = formatter;
         if (valuesSource != null) {
@@ -106,12 +107,12 @@ public class MaxAggregator extends NumericMetricsAggregator.SingleValue {
         if (valuesSource == null || bucket >= maxes.size()) {
             return buildEmptyAggregation();
         }
-        return new InternalMax(name, maxes.get(bucket), formatter, reducers(),  metaData());
+        return new InternalMax(name, maxes.get(bucket), formatter, pipelineAggregators(),  metaData());
     }
 
     @Override
     public InternalAggregation buildEmptyAggregation() {
-        return new InternalMax(name, Double.NEGATIVE_INFINITY, formatter, reducers(), metaData());
+        return new InternalMax(name, Double.NEGATIVE_INFINITY, formatter, pipelineAggregators(), metaData());
     }
 
     public static class Factory extends ValuesSourceAggregatorFactory.LeafOnly<ValuesSource.Numeric> {
@@ -121,15 +122,16 @@ public class MaxAggregator extends NumericMetricsAggregator.SingleValue {
         }
 
         @Override
-        protected Aggregator createUnmapped(AggregationContext aggregationContext, Aggregator parent, List<Reducer> reducers,
+        protected Aggregator createUnmapped(AggregationContext aggregationContext, Aggregator parent,
-                Map<String, Object> metaData) throws IOException {
+                List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
-            return new MaxAggregator(name, null, config.formatter(), aggregationContext, parent, reducers, metaData);
+            return new MaxAggregator(name, null, config.formatter(), aggregationContext, parent, pipelineAggregators, metaData);
         }
 
         @Override
         protected Aggregator doCreateInternal(ValuesSource.Numeric valuesSource, AggregationContext aggregationContext, Aggregator parent,
-                boolean collectsFromSingleBucket, List<Reducer> reducers, Map<String, Object> metaData) throws IOException {
+                boolean collectsFromSingleBucket, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData)
-            return new MaxAggregator(name, valuesSource, config.formatter(), aggregationContext, parent, reducers, metaData);
+                throws IOException {
+            return new MaxAggregator(name, valuesSource, config.formatter(), aggregationContext, parent, pipelineAggregators, metaData);
         }
     }