Statistical Facet: Allow to compute statistical facets on more than one field, closes #436.

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

@@ -30,6 +30,7 @@ import java.io.IOException;
  * @author kimchy (shay.banon)
  */
 public class StatisticalFacetBuilder extends AbstractFacetBuilder {
+    private String[] fieldsNames;
     private String fieldName;
 
     public StatisticalFacetBuilder(String name) {
@@ -41,6 +42,14 @@ public class StatisticalFacetBuilder extends AbstractFacetBuilder {
         return this;
     }
 
+    /**
+     * The fields the terms will be collected from.
+     */
+    public StatisticalFacetBuilder fields(String... fields) {
+        this.fieldsNames = fields;
+        return this;
+    }
+
     public StatisticalFacetBuilder global(boolean global) {
         this.global = global;
         return this;
@@ -52,13 +61,21 @@ public class StatisticalFacetBuilder extends AbstractFacetBuilder {
     }
 
     @Override public void toXContent(XContentBuilder builder, Params params) throws IOException {
-        if (fieldName == null) {
+        if (fieldName == null && fieldsNames == null) {
             throw new SearchSourceBuilderException("field must be set on statistical facet for facet [" + name + "]");
         }
         builder.startObject(name);
 
         builder.startObject(StatisticalFacetCollectorParser.NAME);
-        builder.field("field", fieldName);
+        if (fieldsNames != null) {
+            if (fieldsNames.length == 1) {
+                builder.field("field", fieldsNames[0]);
+            } else {
+                builder.field("fields", fieldsNames);
+            }
+        } else {
+            builder.field("field", fieldName);
+        }
         builder.endObject();
 
         addFilterFacetAndGlobal(builder, params);

modules/elasticsearch/src/main/java/org/elasticsearch/search/facets/statistical/StatisticalFacetCollectorParser.java

@@ -19,6 +19,7 @@
 
 package org.elasticsearch.search.facets.statistical;
 
+import org.elasticsearch.common.collect.Lists;
 import org.elasticsearch.common.thread.ThreadLocals;
 import org.elasticsearch.common.xcontent.XContentParser;
 import org.elasticsearch.search.facets.FacetPhaseExecutionException;
@@ -28,6 +29,7 @@ import org.elasticsearch.search.internal.SearchContext;
 
 import java.io.IOException;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
 /**
@@ -49,12 +51,14 @@ public class StatisticalFacetCollectorParser implements FacetCollectorParser {
 
     @Override public FacetCollector parse(String facetName, XContentParser parser, SearchContext context) throws IOException {
         String field = null;
+        String[] fieldsNames = null;
 
-        String currentFieldName = null;
         String script = null;
         String scriptLang = null;
         Map<String, Object> params = cachedParams.get().get();
         params.clear();
+
+        String currentFieldName = null;
         XContentParser.Token token;
         while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
             if (token == XContentParser.Token.FIELD_NAME) {
@@ -63,6 +67,14 @@ public class StatisticalFacetCollectorParser implements FacetCollectorParser {
                 if ("params".equals(currentFieldName)) {
                     params = parser.map();
                 }
+            } else if (token == XContentParser.Token.START_ARRAY) {
+                if ("fields".equals(currentFieldName)) {
+                    List<String> fields = Lists.newArrayListWithCapacity(4);
+                    while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
+                        fields.add(parser.text());
+                    }
+                    fieldsNames = fields.toArray(new String[fields.size()]);
+                }
             } else if (token.isValue()) {
                 if ("field".equals(currentFieldName)) {
                     field = parser.text();
@@ -73,6 +85,9 @@ public class StatisticalFacetCollectorParser implements FacetCollectorParser {
                 }
             }
         }
+        if (fieldsNames != null) {
+            return new StatisticalFieldsFacetCollector(facetName, fieldsNames, context);
+        }
         if (script == null && field == null) {
             throw new FacetPhaseExecutionException(facetName, "statistical facet requires either [script] or [field] to be set");
         }

modules/elasticsearch/src/main/java/org/elasticsearch/search/facets/statistical/StatisticalFieldsFacetCollector.java

@@ -0,0 +1,132 @@
+/*
+ * 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.search.facets.statistical;
+
+import org.apache.lucene.index.IndexReader;
+import org.elasticsearch.common.Strings;
+import org.elasticsearch.index.cache.field.data.FieldDataCache;
+import org.elasticsearch.index.field.data.FieldDataType;
+import org.elasticsearch.index.field.data.NumericFieldData;
+import org.elasticsearch.index.mapper.FieldMapper;
+import org.elasticsearch.search.facets.Facet;
+import org.elasticsearch.search.facets.FacetPhaseExecutionException;
+import org.elasticsearch.search.facets.support.AbstractFacetCollector;
+import org.elasticsearch.search.internal.SearchContext;
+
+import java.io.IOException;
+
+/**
+ * @author kimchy (shay.banon)
+ */
+public class StatisticalFieldsFacetCollector extends AbstractFacetCollector {
+
+    private final String[] fieldsNames;
+
+    private final String[] indexFieldsNames;
+
+    private final FieldDataCache fieldDataCache;
+
+    private final FieldDataType[] fieldsDataType;
+
+    private NumericFieldData[] fieldsData;
+
+    private final StatsProc statsProc = new StatsProc();
+
+    public StatisticalFieldsFacetCollector(String facetName, String[] fieldsNames, SearchContext context) {
+        super(facetName);
+        this.fieldsNames = fieldsNames;
+        this.fieldDataCache = context.fieldDataCache();
+
+        fieldsDataType = new FieldDataType[fieldsNames.length];
+        fieldsData = new NumericFieldData[fieldsNames.length];
+        indexFieldsNames = new String[fieldsNames.length];
+
+
+        for (int i = 0; i < fieldsNames.length; i++) {
+            FieldMapper mapper = context.mapperService().smartNameFieldMapper(fieldsNames[i]);
+            if (mapper == null) {
+                throw new FacetPhaseExecutionException(facetName, "No mapping found for field [" + fieldsNames[i] + "]");
+            }
+            indexFieldsNames[i] = mapper.names().indexName();
+            fieldsDataType[i] = mapper.fieldDataType();
+        }
+    }
+
+    @Override protected void doCollect(int doc) throws IOException {
+        for (NumericFieldData fieldData : fieldsData) {
+            fieldData.forEachValueInDoc(doc, statsProc);
+        }
+    }
+
+    @Override protected void doSetNextReader(IndexReader reader, int docBase) throws IOException {
+        for (int i = 0; i < fieldsNames.length; i++) {
+            fieldsData[i] = (NumericFieldData) fieldDataCache.cache(fieldsDataType[i], reader, indexFieldsNames[i]);
+        }
+    }
+
+    @Override public Facet facet() {
+        return new InternalStatisticalFacet(facetName, Strings.arrayToCommaDelimitedString(fieldsNames), statsProc.min(), statsProc.max(), statsProc.total(), statsProc.sumOfSquares(), statsProc.count());
+    }
+
+    public static class StatsProc implements NumericFieldData.DoubleValueInDocProc {
+
+        private double min = Double.NaN;
+
+        private double max = Double.NaN;
+
+        private double total = 0;
+
+        private double sumOfSquares = 0.0;
+
+        private long count;
+
+        @Override public void onValue(int docId, double value) {
+            if (value < min || Double.isNaN(min)) {
+                min = value;
+            }
+            if (value > max || Double.isNaN(max)) {
+                max = value;
+            }
+            sumOfSquares += value * value;
+            total += value;
+            count++;
+        }
+
+        public final double min() {
+            return min;
+        }
+
+        public final double max() {
+            return max;
+        }
+
+        public final double total() {
+            return total;
+        }
+
+        public final long count() {
+            return count;
+        }
+
+        public final double sumOfSquares() {
+            return sumOfSquares;
+        }
+    }
+}

modules/elasticsearch/src/main/java/org/elasticsearch/search/facets/terms/TermsFacetCollectorParser.java

@@ -47,9 +47,7 @@ public class TermsFacetCollectorParser implements FacetCollectorParser {
         String field = null;
         int size = 10;
 
-        String fieldName = null;
         String[] fieldsNames = null;
-        XContentParser.Token token;
         ImmutableSet<String> excluded = ImmutableSet.of();
         String regex = null;
         String regexFlags = null;
@@ -57,21 +55,24 @@ public class TermsFacetCollectorParser implements FacetCollectorParser {
         String scriptLang = null;
         String script = null;
         Map<String, Object> params = null;
+
+        String currentFieldName = null;
+        XContentParser.Token token;
         while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
             if (token == XContentParser.Token.FIELD_NAME) {
-                fieldName = parser.currentName();
+                currentFieldName = parser.currentName();
             } else if (token == XContentParser.Token.START_OBJECT) {
-                if ("params".equals(fieldName)) {
+                if ("params".equals(currentFieldName)) {
                     params = parser.map();
                 }
             } else if (token == XContentParser.Token.START_ARRAY) {
-                if ("exclude".equals(fieldName)) {
+                if ("exclude".equals(currentFieldName)) {
                     ImmutableSet.Builder<String> builder = ImmutableSet.builder();
                     while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
                         builder.add(parser.text());
                     }
                     excluded = builder.build();
-                } else if ("fields".equals(fieldName)) {
+                } else if ("fields".equals(currentFieldName)) {
                     List<String> fields = Lists.newArrayListWithCapacity(4);
                     while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
                         fields.add(parser.text());
@@ -79,21 +80,21 @@ public class TermsFacetCollectorParser implements FacetCollectorParser {
                     fieldsNames = fields.toArray(new String[fields.size()]);
                 }
             } else if (token.isValue()) {
-                if ("field".equals(fieldName)) {
+                if ("field".equals(currentFieldName)) {
                     field = parser.text();
-                } else if ("script_field".equals(fieldName)) {
+                } else if ("script_field".equals(currentFieldName)) {
                     script = parser.text();
-                } else if ("size".equals(fieldName)) {
+                } else if ("size".equals(currentFieldName)) {
                     size = parser.intValue();
-                } else if ("regex".equals(fieldName)) {
+                } else if ("regex".equals(currentFieldName)) {
                     regex = parser.text();
-                } else if ("regex_flags".equals(fieldName) || "regexFlags".equals(fieldName)) {
+                } else if ("regex_flags".equals(currentFieldName) || "regexFlags".equals(currentFieldName)) {
                     regexFlags = parser.text();
-                } else if ("order".equals(fieldName) || "comparator".equals(field)) {
+                } else if ("order".equals(currentFieldName) || "comparator".equals(field)) {
                     comparatorType = TermsFacet.ComparatorType.fromString(parser.text());
-                } else if ("script".equals(fieldName)) {
+                } else if ("script".equals(currentFieldName)) {
                     script = parser.text();
-                } else if ("lang".equals(fieldName)) {
+                } else if ("lang".equals(currentFieldName)) {
                     scriptLang = parser.text();
                 }
             }

modules/test/integration/src/test/java/org/elasticsearch/test/integration/search/facets/SimpleFacetsTests.java

@@ -560,6 +560,22 @@ public class SimpleFacetsTests extends AbstractNodesTests {
         assertThat(facet.mean(), equalTo(3d));
         assertThat(facet.sumOfSquares(), equalTo(20d));
 
+        // test multi field facet
+        searchResponse = client.prepareSearch()
+                .setQuery(matchAllQuery())
+                .addFacet(statisticalFacet("stats").fields("num", "multi_num"))
+                .execute().actionGet();
+
+
+        facet = searchResponse.facets().facet("stats");
+        assertThat(facet.name(), equalTo(facet.name()));
+        assertThat(facet.count(), equalTo(6l));
+        assertThat(facet.total(), equalTo(13d));
+        assertThat(facet.min(), equalTo(1d));
+        assertThat(facet.max(), equalTo(4d));
+        assertThat(facet.mean(), equalTo(13d / 6d));
+        assertThat(facet.sumOfSquares(), equalTo(35d));
+
         // test cross field facet using the same facet name...
         searchResponse = client.prepareSearch()
                 .setQuery(matchAllQuery())