Nested Objects Facets Support, closes #1098.

modules/elasticsearch/src/main/java/org/elasticsearch/index/query/HasChildQueryParser.java

@@ -7,7 +7,7 @@
  * "License"); you may not use this file except in compliance
  * with the License.  You may obtain a copy of the License at
  *
- * http://www.apache.org/licenses/LICENSE-2.0
+ *    http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing,
  * software distributed under the License is distributed on an

modules/elasticsearch/src/main/java/org/elasticsearch/index/query/NestedQueryBuilder.java

@@ -33,6 +33,8 @@ public class NestedQueryBuilder extends BaseQueryBuilder {
 
     private float boost = 1.0f;
 
+    private String scope;
+
     public NestedQueryBuilder(String path, QueryBuilder queryBuilder) {
         this.path = path;
         this.queryBuilder = queryBuilder;
@@ -46,6 +48,11 @@ public class NestedQueryBuilder extends BaseQueryBuilder {
         return this;
     }
 
+    public NestedQueryBuilder scope(String scope) {
+        this.scope = scope;
+        return this;
+    }
+
     /**
      * Sets the boost for this query.  Documents matching this query will (in addition to the normal
      * weightings) have their score multiplied by the boost provided.
@@ -63,6 +70,9 @@ public class NestedQueryBuilder extends BaseQueryBuilder {
         if (scoreMode != null) {
             builder.field("score_mode", scoreMode);
         }
+        if (scope != null) {
+            builder.field("_scope", scope);
+        }
         if (boost != 1.0f) {
             builder.field("boost", boost);
         }

modules/elasticsearch/src/main/java/org/elasticsearch/index/query/NestedQueryParser.java

@@ -32,6 +32,7 @@ import org.elasticsearch.index.mapper.MapperService;
 import org.elasticsearch.index.mapper.object.ObjectMapper;
 import org.elasticsearch.index.search.nested.BlockJoinQuery;
 import org.elasticsearch.index.search.nested.NonNestedDocsFilter;
+import org.elasticsearch.search.internal.SearchContext;
 
 import java.io.IOException;
 
@@ -52,6 +53,7 @@ public class NestedQueryParser implements QueryParser {
         Query query = null;
         Filter filter = null;
         float boost = 1.0f;
+        String scope = null;
         String path = null;
         BlockJoinQuery.ScoreMode scoreMode = BlockJoinQuery.ScoreMode.Avg;
 
@@ -77,6 +79,8 @@ public class NestedQueryParser implements QueryParser {
                     path = parser.text();
                 } else if ("boost".equals(currentFieldName)) {
                     boost = parser.floatValue();
+                } else if ("_scope".equals(currentFieldName)) {
+                    scope = parser.text();
                 } else if ("score_mode".equals(currentFieldName) || "scoreMode".equals(scoreMode)) {
                     String sScoreMode = parser.text();
                     if ("avg".equals(sScoreMode)) {
@@ -137,6 +141,11 @@ public class NestedQueryParser implements QueryParser {
         parentFilterContext.set(currentParentFilterContext);
 
         BlockJoinQuery joinQuery = new BlockJoinQuery(query, parentFilter, scoreMode);
+
+        if (scope != null) {
+            SearchContext.current().addNestedQuery(scope, joinQuery);
+        }
+
         return joinQuery;
     }
 

modules/elasticsearch/src/main/java/org/elasticsearch/index/search/nested/BlockJoinQuery.java

@@ -21,18 +21,11 @@ package org.elasticsearch.index.search.nested;
 
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.Term;
-import org.apache.lucene.search.BooleanClause;
+import org.apache.lucene.search.*;
-import org.apache.lucene.search.DocIdSet;
-import org.apache.lucene.search.DocIdSetIterator;
-import org.apache.lucene.search.Explanation;
-import org.apache.lucene.search.Filter;
-import org.apache.lucene.search.Query;
-import org.apache.lucene.search.Scorer;
-import org.apache.lucene.search.Searcher;
-import org.apache.lucene.search.Weight;
 import org.apache.lucene.util.ArrayUtil;
 import org.apache.lucene.util.OpenBitSet;
 import org.elasticsearch.common.lucene.docset.OpenBitDocSet;
+import org.elasticsearch.common.lucene.search.NoopCollector;
 
 import java.io.IOException;
 import java.util.Set;
@@ -77,8 +70,7 @@ import java.util.Set;
  * @lucene.experimental
  */
 
-// LUCENE MONITOR: Track, additions include:
+// LUCENE MONITOR: Track CHANGE
-// --
 public class BlockJoinQuery extends Query {
 
     public static enum ScoreMode {None, Avg, Max, Total}
@@ -88,6 +80,13 @@ public class BlockJoinQuery extends Query {
     private final Filter parentsFilter;
     private final Query childQuery;
 
+    private Collector childCollector = NoopCollector.NOOP_COLLECTOR;
+
+    public BlockJoinQuery setCollector(Collector collector) {
+        this.childCollector = collector;
+        return this;
+    }
+
     // If we are rewritten, this is the original childQuery we
     // were passed; we use this for .equals() and
     // .hashCode().  This makes rewritten query equal the
@@ -114,7 +113,7 @@ public class BlockJoinQuery extends Query {
 
     @Override
     public Weight createWeight(Searcher searcher) throws IOException {
-        return new BlockJoinWeight(this, childQuery.createWeight(searcher), parentsFilter, scoreMode);
+        return new BlockJoinWeight(this, childQuery.createWeight(searcher), parentsFilter, scoreMode, childCollector);
     }
 
     private static class BlockJoinWeight extends Weight {
@@ -122,13 +121,15 @@ public class BlockJoinQuery extends Query {
         private final Weight childWeight;
         private final Filter parentsFilter;
         private final ScoreMode scoreMode;
+        private final Collector childCollector;
 
-        public BlockJoinWeight(Query joinQuery, Weight childWeight, Filter parentsFilter, ScoreMode scoreMode) {
+        public BlockJoinWeight(Query joinQuery, Weight childWeight, Filter parentsFilter, ScoreMode scoreMode, Collector childCollector) {
             super();
             this.joinQuery = joinQuery;
             this.childWeight = childWeight;
             this.parentsFilter = parentsFilter;
             this.scoreMode = scoreMode;
+            this.childCollector = childCollector;
         }
 
         @Override
@@ -183,7 +184,13 @@ public class BlockJoinQuery extends Query {
                 throw new IllegalStateException("parentFilter must return OpenBitSet; got " + parents);
             }
 
-            return new BlockJoinScorer(this, childScorer, (OpenBitSet) parents, firstChildDoc, scoreMode);
+            // CHANGE:
+            if (childCollector != null) {
+                childCollector.setNextReader(reader, 0);
+                childCollector.setScorer(childScorer);
+            }
+
+            return new BlockJoinScorer(this, childScorer, (OpenBitSet) parents, firstChildDoc, scoreMode, childCollector);
         }
 
         @Override
@@ -203,6 +210,7 @@ public class BlockJoinQuery extends Query {
         private final Scorer childScorer;
         private final OpenBitSet parentBits;
         private final ScoreMode scoreMode;
+        private final Collector childCollector;
         private int parentDoc;
         private float parentScore;
         private int nextChildDoc;
@@ -211,12 +219,13 @@ public class BlockJoinQuery extends Query {
         private float[] pendingChildScores;
         private int childDocUpto;
 
-        public BlockJoinScorer(Weight weight, Scorer childScorer, OpenBitSet parentBits, int firstChildDoc, ScoreMode scoreMode) {
+        public BlockJoinScorer(Weight weight, Scorer childScorer, OpenBitSet parentBits, int firstChildDoc, ScoreMode scoreMode, Collector childCollector) {
             super(weight);
             //System.out.println("Q.init firstChildDoc=" + firstChildDoc);
             this.parentBits = parentBits;
             this.childScorer = childScorer;
             this.scoreMode = scoreMode;
+            this.childCollector = childCollector;
             if (scoreMode != ScoreMode.None) {
                 pendingChildScores = new float[5];
             }
@@ -292,6 +301,10 @@ public class BlockJoinQuery extends Query {
                     maxScore = Math.max(childScore, maxScore);
                     totalScore += childScore;
                 }
+
+                // CHANGE:
+                childCollector.collect(nextChildDoc);
+
                 childDocUpto++;
                 nextChildDoc = childScorer.nextDoc();
             } while (nextChildDoc < parentDoc);
@@ -368,7 +381,7 @@ public class BlockJoinQuery extends Query {
             return new BlockJoinQuery(childQuery,
                     childRewrite,
                     parentsFilter,
-                    scoreMode);
+                    scoreMode).setCollector(childCollector);
         } else {
             return this;
         }
@@ -415,6 +428,6 @@ public class BlockJoinQuery extends Query {
     public Object clone() {
         return new BlockJoinQuery((Query) origChildQuery.clone(),
                 parentsFilter,
-                scoreMode);
+                scoreMode).setCollector(childCollector);
     }
 }

modules/elasticsearch/src/main/java/org/elasticsearch/index/search/nested/NestedChildrenCollector.java

@@ -0,0 +1,89 @@
+/*
+ * Licensed to Elastic Search and Shay Banon under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. Elastic Search licenses this
+ * file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.index.search.nested;
+
+import org.apache.lucene.index.IndexReader;
+import org.apache.lucene.search.Filter;
+import org.apache.lucene.search.Scorer;
+import org.apache.lucene.util.OpenBitSet;
+import org.elasticsearch.common.lucene.docset.DocSet;
+import org.elasticsearch.common.lucene.docset.DocSets;
+import org.elasticsearch.common.lucene.docset.OpenBitDocSet;
+import org.elasticsearch.search.facet.Facet;
+import org.elasticsearch.search.facet.FacetCollector;
+
+import java.io.IOException;
+
+/**
+ * A collector that accepts parent docs, and calls back the collect on child docs of that parent.
+ */
+public class NestedChildrenCollector extends FacetCollector {
+
+    private final FacetCollector collector;
+
+    private final Filter parentFilter;
+
+    private final Filter childFilter;
+
+    private DocSet childDocs;
+
+    private OpenBitSet parentDocs;
+
+    private IndexReader currentReader;
+
+    public NestedChildrenCollector(FacetCollector collector, Filter parentFilter, Filter childFilter) {
+        this.collector = collector;
+        this.parentFilter = parentFilter;
+        this.childFilter = childFilter;
+    }
+
+    @Override public Facet facet() {
+        return collector.facet();
+    }
+
+    @Override public void setFilter(Filter filter) {
+        // delegate the facet_filter to the children
+        collector.setFilter(filter);
+    }
+
+    @Override public void setScorer(Scorer scorer) throws IOException {
+        collector.setScorer(scorer);
+    }
+
+    @Override public void setNextReader(IndexReader reader, int docBase) throws IOException {
+        collector.setNextReader(reader, docBase);
+        currentReader = reader;
+        childDocs = DocSets.convert(reader, childFilter.getDocIdSet(reader));
+        parentDocs = ((OpenBitDocSet) parentFilter.getDocIdSet(reader)).set();
+    }
+
+    @Override public boolean acceptsDocsOutOfOrder() {
+        return collector.acceptsDocsOutOfOrder();
+    }
+
+    @Override public void collect(int parentDoc) throws IOException {
+        int prevParentDoc = parentDocs.prevSetBit(parentDoc - 1);
+        for (int i = (parentDoc - 1); i > prevParentDoc; i--) {
+            if (!currentReader.isDeleted(i) && childDocs.get(i)) {
+                collector.collect(i);
+            }
+        }
+    }
+}

modules/elasticsearch/src/main/java/org/elasticsearch/search/facet/AbstractFacetBuilder.java

@@ -37,6 +37,8 @@ public abstract class AbstractFacetBuilder implements ToXContent {
 
     protected FilterBuilder facetFilter;
 
+    protected String nested;
+
     protected AbstractFacetBuilder(String name) {
         this.name = name;
     }
@@ -46,6 +48,15 @@ public abstract class AbstractFacetBuilder implements ToXContent {
         return this;
     }
 
+    /**
+     * Sets the nested path the facet will execute on. A match (root object) will then cause all the
+     * nested objects matching the path to be computed into the facet.
+     */
+    public AbstractFacetBuilder nested(String nested) {
+        this.nested = nested;
+        return this;
+    }
+
     /**
      * Marks the facet to run in a global scope, not bounded by any query.
      */
@@ -68,6 +79,10 @@ public abstract class AbstractFacetBuilder implements ToXContent {
             facetFilter.toXContent(builder, params);
         }
 
+        if (nested != null) {
+            builder.field("nested", nested);
+        }
+
         if (scope != null) {
             builder.field("scope", scope);
         }

modules/elasticsearch/src/main/java/org/elasticsearch/search/facet/FacetParseElement.java

@@ -23,6 +23,10 @@ import org.apache.lucene.search.Filter;
 import org.elasticsearch.common.collect.Lists;
 import org.elasticsearch.common.inject.Inject;
 import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.index.mapper.MapperService;
+import org.elasticsearch.index.mapper.object.ObjectMapper;
+import org.elasticsearch.index.search.nested.NestedChildrenCollector;
+import org.elasticsearch.index.search.nested.NonNestedDocsFilter;
 import org.elasticsearch.search.SearchParseElement;
 import org.elasticsearch.search.SearchParseException;
 import org.elasticsearch.search.internal.ContextIndexSearcher;
@@ -72,6 +76,7 @@ public class FacetParseElement implements SearchParseElement {
                 String facetFieldName = null;
                 Filter filter = null;
                 boolean cacheFilter = true;
+                String nestedPath = null;
                 while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
                     if (token == XContentParser.Token.FIELD_NAME) {
                         facetFieldName = parser.currentName();
@@ -90,10 +95,12 @@ public class FacetParseElement implements SearchParseElement {
                             if (parser.booleanValue()) {
                                 scope = ContextIndexSearcher.Scopes.GLOBAL;
                             }
-                        } else if ("scope".equals(facetFieldName)) {
+                        } else if ("scope".equals(facetFieldName) || "_scope".equals(facetFieldName)) {
                             scope = parser.text();
                         } else if ("cache_filter".equals(facetFieldName) || "cacheFilter".equals(facetFieldName)) {
                             cacheFilter = parser.booleanValue();
+                        } else if ("nested".equals(facetFieldName)) {
+                            nestedPath = parser.text();
                         }
                     }
                 }
@@ -104,6 +111,22 @@ public class FacetParseElement implements SearchParseElement {
                     facet.setFilter(filter);
                 }
 
+                if (nestedPath != null) {
+                    // its a nested facet, wrap the collector with a facet one...
+                    MapperService.SmartNameObjectMapper mapper = context.mapperService().smartNameObjectMapper(nestedPath);
+                    if (mapper == null) {
+                        throw new SearchParseException(context, "facet nested path [" + nestedPath + "] not found");
+                    }
+                    ObjectMapper objectMapper = mapper.mapper();
+                    if (objectMapper == null) {
+                        throw new SearchParseException(context, "facet nested path [" + nestedPath + "] not found");
+                    }
+                    if (!objectMapper.nested().isNested()) {
+                        throw new SearchParseException(context, "facet nested path [" + nestedPath + "] is not nested");
+                    }
+                    facet = new NestedChildrenCollector(facet, context.filterCache().cache(NonNestedDocsFilter.INSTANCE), context.filterCache().cache(objectMapper.nestedTypeFilter()));
+                }
+
                 if (facetCollectors == null) {
                     facetCollectors = Lists.newArrayList();
                 }

modules/elasticsearch/src/main/java/org/elasticsearch/search/facet/FacetPhase.java

@@ -31,6 +31,7 @@ import org.elasticsearch.common.collect.Lists;
 import org.elasticsearch.common.collect.Maps;
 import org.elasticsearch.common.inject.Inject;
 import org.elasticsearch.common.lucene.search.Queries;
+import org.elasticsearch.index.search.nested.BlockJoinQuery;
 import org.elasticsearch.search.SearchParseElement;
 import org.elasticsearch.search.SearchPhase;
 import org.elasticsearch.search.internal.ContextIndexSearcher;
@@ -61,6 +62,19 @@ public class FacetPhase implements SearchPhase {
     }
 
     @Override public void preProcess(SearchContext context) {
+        // add specific facets to nested queries...
+        if (context.nestedQueries() != null) {
+            for (Map.Entry<String, BlockJoinQuery> entry : context.nestedQueries().entrySet()) {
+                List<Collector> collectors = context.searcher().removeCollectors(entry.getKey());
+                if (collectors != null && !collectors.isEmpty()) {
+                    if (collectors.size() == 1) {
+                        entry.getValue().setCollector(collectors.get(0));
+                    } else {
+                        entry.getValue().setCollector(MultiCollector.wrap(collectors.toArray(new Collector[collectors.size()])));
+                    }
+                }
+            }
+        }
     }
 
     @Override public void execute(SearchContext context) throws ElasticSearchException {

modules/elasticsearch/src/main/java/org/elasticsearch/search/facet/datehistogram/DateHistogramFacetBuilder.java

@@ -150,6 +150,16 @@ public class DateHistogramFacetBuilder extends AbstractFacetBuilder {
         return this;
     }
 
+    /**
+     * Sets the nested path the facet will execute on. A match (root object) will then cause all the
+     * nested objects matching the path to be computed into the facet.
+     */
+    public DateHistogramFacetBuilder nested(String nested) {
+        this.nested = nested;
+        return this;
+    }
+
+
     @Override public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
         if (keyFieldName == null) {
             throw new SearchSourceBuilderException("field must be set on date histogram facet for facet [" + name + "]");

modules/elasticsearch/src/main/java/org/elasticsearch/search/facet/filter/FilterFacetBuilder.java

@@ -58,6 +58,15 @@ public class FilterFacetBuilder extends AbstractFacetBuilder {
         return this;
     }
 
+    /**
+     * Sets the nested path the facet will execute on. A match (root object) will then cause all the
+     * nested objects matching the path to be computed into the facet.
+     */
+    public FilterFacetBuilder nested(String nested) {
+        this.nested = nested;
+        return this;
+    }
+
     public FilterFacetBuilder filter(FilterBuilder filter) {
         this.filter = filter;
         return this;

modules/elasticsearch/src/main/java/org/elasticsearch/search/facet/geodistance/GeoDistanceFacetBuilder.java

@@ -217,6 +217,15 @@ public class GeoDistanceFacetBuilder extends AbstractFacetBuilder {
         return this;
     }
 
+    /**
+     * Sets the nested path the facet will execute on. A match (root object) will then cause all the
+     * nested objects matching the path to be computed into the facet.
+     */
+    public GeoDistanceFacetBuilder nested(String nested) {
+        this.nested = nested;
+        return this;
+    }
+
     @Override public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
         if (fieldName == null) {
             throw new SearchSourceBuilderException("field must be set on geo_distance facet for facet [" + name + "]");

modules/elasticsearch/src/main/java/org/elasticsearch/search/facet/histogram/HistogramFacetBuilder.java

@@ -132,6 +132,15 @@ public class HistogramFacetBuilder extends AbstractFacetBuilder {
         return this;
     }
 
+    /**
+     * Sets the nested path the facet will execute on. A match (root object) will then cause all the
+     * nested objects matching the path to be computed into the facet.
+     */
+    public HistogramFacetBuilder nested(String nested) {
+        this.nested = nested;
+        return this;
+    }
+
     @Override public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
         if (keyFieldName == null) {
             throw new SearchSourceBuilderException("field must be set on histogram facet for facet [" + name + "]");

modules/elasticsearch/src/main/java/org/elasticsearch/search/facet/histogram/HistogramScriptFacetBuilder.java

@@ -118,6 +118,15 @@ public class HistogramScriptFacetBuilder extends AbstractFacetBuilder {
         return this;
     }
 
+    /**
+     * Sets the nested path the facet will execute on. A match (root object) will then cause all the
+     * nested objects matching the path to be computed into the facet.
+     */
+    public HistogramScriptFacetBuilder nested(String nested) {
+        this.nested = nested;
+        return this;
+    }
+
     @Override public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
         if (keyScript == null && keyFieldName == null) {
             throw new SearchSourceBuilderException("key_script or key_field must be set on histogram script facet for facet [" + name + "]");

modules/elasticsearch/src/main/java/org/elasticsearch/search/facet/query/QueryFacetBuilder.java

@@ -59,6 +59,15 @@ public class QueryFacetBuilder extends AbstractFacetBuilder {
         return this;
     }
 
+    /**
+     * Sets the nested path the facet will execute on. A match (root object) will then cause all the
+     * nested objects matching the path to be computed into the facet.
+     */
+    public QueryFacetBuilder nested(String nested) {
+        this.nested = nested;
+        return this;
+    }
+
     public QueryFacetBuilder query(QueryBuilder query) {
         this.query = query;
         return this;

modules/elasticsearch/src/main/java/org/elasticsearch/search/facet/range/RangeFacetBuilder.java

@@ -149,6 +149,15 @@ public class RangeFacetBuilder extends AbstractFacetBuilder {
         return this;
     }
 
+    /**
+     * Sets the nested path the facet will execute on. A match (root object) will then cause all the
+     * nested objects matching the path to be computed into the facet.
+     */
+    public RangeFacetBuilder nested(String nested) {
+        this.nested = nested;
+        return this;
+    }
+
     @Override public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
         if (keyFieldName == null) {
             throw new SearchSourceBuilderException("field must be set on range facet for facet [" + name + "]");

modules/elasticsearch/src/main/java/org/elasticsearch/search/facet/range/RangeScriptFacetBuilder.java

@@ -125,6 +125,15 @@ public class RangeScriptFacetBuilder extends AbstractFacetBuilder {
         return this;
     }
 
+    /**
+     * Sets the nested path the facet will execute on. A match (root object) will then cause all the
+     * nested objects matching the path to be computed into the facet.
+     */
+    public RangeScriptFacetBuilder nested(String nested) {
+        this.nested = nested;
+        return this;
+    }
+
     @Override public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
         if (keyScript == null) {
             throw new SearchSourceBuilderException("key_script must be set on range script facet for facet [" + name + "]");

modules/elasticsearch/src/main/java/org/elasticsearch/search/facet/statistical/StatisticalFacetBuilder.java

@@ -71,6 +71,15 @@ public class StatisticalFacetBuilder extends AbstractFacetBuilder {
         return this;
     }
 
+    /**
+     * Sets the nested path the facet will execute on. A match (root object) will then cause all the
+     * nested objects matching the path to be computed into the facet.
+     */
+    public StatisticalFacetBuilder nested(String nested) {
+        this.nested = nested;
+        return this;
+    }
+
     @Override public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
         if (fieldName == null && fieldsNames == null) {
             throw new SearchSourceBuilderException("field must be set on statistical facet for facet [" + name + "]");

modules/elasticsearch/src/main/java/org/elasticsearch/search/facet/statistical/StatisticalScriptFacetBuilder.java

@@ -61,6 +61,15 @@ public class StatisticalScriptFacetBuilder extends AbstractFacetBuilder {
         return this;
     }
 
+    /**
+     * Sets the nested path the facet will execute on. A match (root object) will then cause all the
+     * nested objects matching the path to be computed into the facet.
+     */
+    public StatisticalScriptFacetBuilder nested(String nested) {
+        this.nested = nested;
+        return this;
+    }
+
     /**
      * The language of the script.
      */

modules/elasticsearch/src/main/java/org/elasticsearch/search/facet/terms/TermsFacetBuilder.java

@@ -83,6 +83,15 @@ public class TermsFacetBuilder extends AbstractFacetBuilder {
         return this;
     }
 
+    /**
+     * Sets the nested path the facet will execute on. A match (root object) will then cause all the
+     * nested objects matching the path to be computed into the facet.
+     */
+    public TermsFacetBuilder nested(String nested) {
+        this.nested = nested;
+        return this;
+    }
+
     /**
      * The field the terms will be collected from.
      */

modules/elasticsearch/src/main/java/org/elasticsearch/search/internal/SearchContext.java

@@ -36,6 +36,7 @@ import org.elasticsearch.index.engine.Engine;
 import org.elasticsearch.index.mapper.MapperService;
 import org.elasticsearch.index.query.IndexQueryParserService;
 import org.elasticsearch.index.query.ParsedQuery;
+import org.elasticsearch.index.search.nested.BlockJoinQuery;
 import org.elasticsearch.index.service.IndexService;
 import org.elasticsearch.index.similarity.SimilarityService;
 import org.elasticsearch.script.ScriptService;
@@ -50,7 +51,9 @@ import org.elasticsearch.search.lookup.SearchLookup;
 import org.elasticsearch.search.query.QuerySearchResult;
 
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
 /**
  * @author kimchy (shay.banon)
@@ -148,6 +151,8 @@ public class SearchContext implements Releasable {
 
     private List<ScopePhase> scopePhases = null;
 
+    private Map<String, BlockJoinQuery> nestedQueries;
+
     public SearchContext(long id, SearchShardTarget shardTarget, SearchType searchType, int numberOfShards, TimeValue timeout,
                          String[] types, Engine.Searcher engineSearcher, IndexService indexService, ScriptService scriptService) {
         this.id = id;
@@ -486,4 +491,15 @@ public class SearchContext implements Releasable {
         }
         this.scopePhases.add(scopePhase);
     }
+
+    public Map<String, BlockJoinQuery> nestedQueries() {
+        return this.nestedQueries;
+    }
+
+    public void addNestedQuery(String scope, BlockJoinQuery query) {
+        if (nestedQueries == null) {
+            nestedQueries = new HashMap<String, BlockJoinQuery>();
+        }
+        nestedQueries.put(scope, query);
+    }
 }

modules/test/integration/src/test/java/org/elasticsearch/test/integration/nested/SimpleNestedTests.java

@@ -24,6 +24,9 @@ import org.elasticsearch.action.delete.DeleteResponse;
 import org.elasticsearch.action.get.GetResponse;
 import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.client.Client;
+import org.elasticsearch.common.settings.ImmutableSettings;
+import org.elasticsearch.search.facet.FacetBuilders;
+import org.elasticsearch.search.facet.termsstats.TermsStatsFacet;
 import org.elasticsearch.test.integration.AbstractNodesTests;
 import org.testng.annotations.AfterClass;
 import org.testng.annotations.BeforeClass;
@@ -226,4 +229,85 @@ public class SimpleNestedTests extends AbstractNodesTests {
         assertThat(Arrays.toString(searchResponse.shardFailures()), searchResponse.failedShards(), equalTo(0));
         assertThat(searchResponse.hits().totalHits(), equalTo(0l));
     }
+
+    @Test public void testFacetsSingleShard() throws Exception {
+        testFacets(1);
+    }
+
+    @Test public void testFacetsMultiShards() throws Exception {
+        testFacets(3);
+    }
+
+    private void testFacets(int numberOfShards) throws Exception {
+        client.admin().indices().prepareDelete().execute().actionGet();
+
+        client.admin().indices().prepareCreate("test")
+                .setSettings(ImmutableSettings.settingsBuilder().put("number_of_shards", numberOfShards))
+                .addMapping("type1", jsonBuilder().startObject().startObject("type1").startObject("properties")
+                        .startObject("nested1")
+                        .field("type", "nested").startObject("properties")
+                        .startObject("nested2").field("type", "nested").endObject()
+                        .endObject().endObject()
+                        .endObject().endObject().endObject())
+                .execute().actionGet();
+
+        client.admin().cluster().prepareHealth().setWaitForGreenStatus().execute().actionGet();
+
+        client.prepareIndex("test", "type1", "1").setSource(jsonBuilder()
+                .startObject()
+                .field("field", "value")
+                .startArray("nested1")
+                .startObject().field("field1_1", "1").startArray("nested2").startObject().field("field2_1", "blue").field("field2_2", 5).endObject().startObject().field("field2_1", "yellow").field("field2_2", 3).endObject().endArray().endObject()
+                .startObject().field("field1_1", "4").startArray("nested2").startObject().field("field2_1", "green").field("field2_2", 6).endObject().startObject().field("field2_1", "blue").field("field2_2", 1).endObject().endArray().endObject()
+                .endArray()
+                .endObject()).execute().actionGet();
+
+        client.prepareIndex("test", "type1", "2").setSource(jsonBuilder()
+                .startObject()
+                .field("field", "value")
+                .startArray("nested1")
+                .startObject().field("field1_1", "2").startArray("nested2").startObject().field("field2_1", "yellow").field("field2_2", 10).endObject().startObject().field("field2_1", "green").field("field2_2", 8).endObject().endArray().endObject()
+                .startObject().field("field1_1", "1").startArray("nested2").startObject().field("field2_1", "blue").field("field2_2", 2).endObject().startObject().field("field2_1", "red").field("field2_2", 12).endObject().endArray().endObject()
+                .endArray()
+                .endObject()).execute().actionGet();
+
+        client.admin().indices().prepareRefresh().execute().actionGet();
+
+        SearchResponse searchResponse = client.prepareSearch("test").setQuery(matchAllQuery())
+                .addFacet(FacetBuilders.termsStatsFacet("facet1").keyField("nested1.nested2.field2_1").valueField("nested1.nested2.field2_2").nested("nested1.nested2"))
+                .execute().actionGet();
+
+        assertThat(Arrays.toString(searchResponse.shardFailures()), searchResponse.failedShards(), equalTo(0));
+        assertThat(searchResponse.hits().totalHits(), equalTo(2l));
+
+        TermsStatsFacet termsStatsFacet = searchResponse.facets().facet("facet1");
+        assertThat(termsStatsFacet.entries().size(), equalTo(4));
+        assertThat(termsStatsFacet.entries().get(0).term(), equalTo("blue"));
+        assertThat(termsStatsFacet.entries().get(0).count(), equalTo(3l));
+        assertThat(termsStatsFacet.entries().get(0).total(), equalTo(8d));
+        assertThat(termsStatsFacet.entries().get(1).term(), equalTo("yellow"));
+        assertThat(termsStatsFacet.entries().get(1).count(), equalTo(2l));
+        assertThat(termsStatsFacet.entries().get(1).total(), equalTo(13d));
+        assertThat(termsStatsFacet.entries().get(2).term(), equalTo("green"));
+        assertThat(termsStatsFacet.entries().get(2).count(), equalTo(2l));
+        assertThat(termsStatsFacet.entries().get(2).total(), equalTo(14d));
+        assertThat(termsStatsFacet.entries().get(3).term(), equalTo("red"));
+        assertThat(termsStatsFacet.entries().get(3).count(), equalTo(1l));
+        assertThat(termsStatsFacet.entries().get(3).total(), equalTo(12d));
+
+        // test scope ones
+        searchResponse = client.prepareSearch("test")
+                .setQuery(nestedQuery("nested1.nested2", termQuery("nested1.nested2.field2_1", "blue")).scope("my"))
+                .addFacet(FacetBuilders.termsStatsFacet("facet1").keyField("nested1.nested2.field2_1").valueField("nested1.nested2.field2_2").scope("my"))
+                .execute().actionGet();
+
+        assertThat(Arrays.toString(searchResponse.shardFailures()), searchResponse.failedShards(), equalTo(0));
+        assertThat(searchResponse.hits().totalHits(), equalTo(2l));
+
+        termsStatsFacet = searchResponse.facets().facet("facet1");
+        assertThat(termsStatsFacet.entries().size(), equalTo(1));
+        assertThat(termsStatsFacet.entries().get(0).term(), equalTo("blue"));
+        assertThat(termsStatsFacet.entries().get(0).count(), equalTo(3l));
+        assertThat(termsStatsFacet.entries().get(0).total(), equalTo(8d));
+    }
 }