lucene-java-3.4.0/lucene/contrib/grouping/src/java/org/apache/lucene/search/grouping/TopGroups.java

   1 package org.apache.lucene.search.grouping;
   2
   3 /**
   4  * Licensed to the Apache Software Foundation (ASF) under one or more
   5  * contributor license agreements.  See the NOTICE file distributed with
   6  * this work for additional information regarding copyright ownership.
   7  * The ASF licenses this file to You under the Apache License, Version 2.0
   8  * (the "License"); you may not use this file except in compliance with
   9  * the License.  You may obtain a copy of the License at
  10  *
  11  *     http://www.apache.org/licenses/LICENSE-2.0
  12  *
  13  * Unless required by applicable law or agreed to in writing, software
  14  * distributed under the License is distributed on an "AS IS" BASIS,
  15  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  16  * See the License for the specific language governing permissions and
  17  * limitations under the License.
  18  */
  19
  20 import java.io.IOException;
  21
  22 import org.apache.lucene.search.ScoreDoc;
  23 import org.apache.lucene.search.Sort;
  24 import org.apache.lucene.search.SortField;
  25 import org.apache.lucene.search.TopDocs;
  26
  27 /** Represents result returned by a grouping search.
  28  *
  29  * @lucene.experimental */
  30 public class TopGroups<GROUP_VALUE_TYPE> {
  31   /** Number of documents matching the search */
  32   public final int totalHitCount;
  33
  34   /** Number of documents grouped into the topN groups */
  35   public final int totalGroupedHitCount;
  36
  37   /** The total number of unique groups. If <code>null</code> this value is not computed. */
  38   public final Integer totalGroupCount;
  39
  40   /** Group results in groupSort order */
  41   public final GroupDocs<GROUP_VALUE_TYPE>[] groups;
  42
  43   /** How groups are sorted against each other */
  44   public final SortField[] groupSort;
  45
  46   /** How docs are sorted within each group */
  47   public final SortField[] withinGroupSort;
  48
  49   public TopGroups(SortField[] groupSort, SortField[] withinGroupSort, int totalHitCount, int totalGroupedHitCount, GroupDocs<GROUP_VALUE_TYPE>[] groups) {
  50     this.groupSort = groupSort;
  51     this.withinGroupSort = withinGroupSort;
  52     this.totalHitCount = totalHitCount;
  53     this.totalGroupedHitCount = totalGroupedHitCount;
  54     this.groups = groups;
  55     this.totalGroupCount = null;
  56   }
  57
  58   public TopGroups(TopGroups<GROUP_VALUE_TYPE> oldTopGroups, Integer totalGroupCount) {
  59     this.groupSort = oldTopGroups.groupSort;
  60     this.withinGroupSort = oldTopGroups.withinGroupSort;
  61     this.totalHitCount = oldTopGroups.totalHitCount;
  62     this.totalGroupedHitCount = oldTopGroups.totalGroupedHitCount;
  63     this.groups = oldTopGroups.groups;
  64     this.totalGroupCount = totalGroupCount;
  65   }
  66
  67   /** Merges an array of TopGroups, for example obtained
  68    *  from the second-pass collector across multiple
  69    *  shards.  Each TopGroups must have been sorted by the
  70    *  same groupSort and docSort, and the top groups passed
  71    *  to all second-pass collectors must be the same.
  72    *
  73    * <b>NOTE</b>: this cannot merge totalGroupCount; ie the
  74    * returned TopGroups will have null totalGroupCount.
  75    *
  76    * <b>NOTE</b>: the topDocs in each GroupDocs is actually
  77    * an instance of TopDocsAndShards
  78    */
  79   public static <T> TopGroups<T> merge(TopGroups<T>[] shardGroups, Sort groupSort, Sort docSort, int docOffset, int docTopN)
  80     throws IOException {
  81
  82     //System.out.println("TopGroups.merge");
  83
  84     if (shardGroups.length == 0) {
  85       return null;
  86     }
  87
  88     int totalHitCount = 0;
  89     int totalGroupedHitCount = 0;
  90
  91     final int numGroups = shardGroups[0].groups.length;
  92     for(TopGroups<T> shard : shardGroups) {
  93       if (numGroups != shard.groups.length) {
  94         throw new IllegalArgumentException("number of groups differs across shards; you must pass same top groups to all shards' second-pass collector");
  95       }
  96       totalHitCount += shard.totalHitCount;
  97       totalGroupedHitCount += shard.totalGroupedHitCount;
  98     }
  99
 100     @SuppressWarnings("unchecked")
 101     final GroupDocs<T>[] mergedGroupDocs = new GroupDocs[numGroups];
 102
 103     final TopDocs[] shardTopDocs = new TopDocs[shardGroups.length];
 104
 105     for(int groupIDX=0;groupIDX<numGroups;groupIDX++) {
 106       final T groupValue = shardGroups[0].groups[groupIDX].groupValue;
 107       //System.out.println("  merge groupValue=" + groupValue + " sortValues=" + Arrays.toString(shardGroups[0].groups[groupIDX].groupSortValues));
 108       float maxScore = Float.MIN_VALUE;
 109       int totalHits = 0;
 110       for(int shardIDX=0;shardIDX<shardGroups.length;shardIDX++) {
 111         //System.out.println("    shard=" + shardIDX);
 112         final TopGroups<T> shard = shardGroups[shardIDX];
 113         final GroupDocs shardGroupDocs = shard.groups[groupIDX];
 114         if (groupValue == null) {
 115           if (shardGroupDocs.groupValue != null) {
 116             throw new IllegalArgumentException("group values differ across shards; you must pass same top groups to all shards' second-pass collector");
 117           }
 118         } else if (!groupValue.equals(shardGroupDocs.groupValue)) {
 119           throw new IllegalArgumentException("group values differ across shards; you must pass same top groups to all shards' second-pass collector");
 120         }
 121
 122         /*
 123         for(ScoreDoc sd : shardGroupDocs.scoreDocs) {
 124           System.out.println("      doc=" + sd.doc);
 125         }
 126         */
 127
 128         shardTopDocs[shardIDX] = new TopDocs(shardGroupDocs.totalHits,
 129                                              shardGroupDocs.scoreDocs,
 130                                              shardGroupDocs.maxScore);
 131         maxScore = Math.max(maxScore, shardGroupDocs.maxScore);
 132         totalHits += shardGroupDocs.totalHits;
 133       }
 134
 135       final TopDocs mergedTopDocs = TopDocs.merge(docSort, docOffset + docTopN, shardTopDocs);
 136
 137       // Slice;
 138       final ScoreDoc[] mergedScoreDocs;
 139       if (docOffset == 0) {
 140         mergedScoreDocs = mergedTopDocs.scoreDocs;
 141       } else if (docOffset >= mergedTopDocs.scoreDocs.length) {
 142         mergedScoreDocs = new ScoreDoc[0];
 143       } else {
 144         mergedScoreDocs = new ScoreDoc[mergedTopDocs.scoreDocs.length - docOffset];
 145         System.arraycopy(mergedTopDocs.scoreDocs,
 146                          docOffset,
 147                          mergedScoreDocs,
 148                          0,
 149                          mergedTopDocs.scoreDocs.length - docOffset);
 150       }
 151       //System.out.println("SHARDS=" + Arrays.toString(mergedTopDocs.shardIndex));
 152       mergedGroupDocs[groupIDX] = new GroupDocs<T>(maxScore,
 153                                                    totalHits,
 154                                                    mergedScoreDocs,
 155                                                    groupValue,
 156                                                    shardGroups[0].groups[groupIDX].groupSortValues);
 157     }
 158
 159     return new TopGroups<T>(groupSort.getSort(),
 160                             docSort == null ? null : docSort.getSort(),
 161                             totalHitCount,
 162                             totalGroupedHitCount,
 163                             mergedGroupDocs);
 164   }
 165 }