content: package org.apache.lucene.search.grouping;
  
  /**
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF 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.
   */
  
  import org.apache.lucene.search.ScoreDoc;
  import org.apache.lucene.search.Sort;
  import org.apache.lucene.search.SortField;
  import org.apache.lucene.search.TopDocs;
  
  import java.io.IOException;
  import java.util.HashMap;
  
  /** Represents result returned by a grouping search.
   *
   * @lucene.experimental */
  public class TopGroups<GROUP_VALUE_TYPE> {
    /** Number of documents matching the search */
    public final int totalHitCount;
  
    /** Number of documents grouped into the topN groups */
    public final int totalGroupedHitCount;
  
    /** The total number of unique groups. If <code>null</code> this value is not computed. */
    public final Integer totalGroupCount;
  
    /** Group results in groupSort order */
    public final GroupDocs<GROUP_VALUE_TYPE>[] groups;
  
    /** How groups are sorted against each other */
    public final SortField[] groupSort;
  
    /** How docs are sorted within each group */
    public final SortField[] withinGroupSort;
  
    public TopGroups(SortField[] groupSort, SortField[] withinGroupSort, int totalHitCount, int totalGroupedHitCount, GroupDocs<GROUP_VALUE_TYPE>[] groups) {
      this.groupSort = groupSort;
      this.withinGroupSort = withinGroupSort;
      this.totalHitCount = totalHitCount;
      this.totalGroupedHitCount = totalGroupedHitCount;
      this.groups = groups;
      this.totalGroupCount = null;
    }
  
    public TopGroups(TopGroups<GROUP_VALUE_TYPE> oldTopGroups, Integer totalGroupCount) {
      this.groupSort = oldTopGroups.groupSort;
      this.withinGroupSort = oldTopGroups.withinGroupSort;
      this.totalHitCount = oldTopGroups.totalHitCount;
      this.totalGroupedHitCount = oldTopGroups.totalGroupedHitCount;
      this.groups = oldTopGroups.groups;
      this.totalGroupCount = totalGroupCount;
    }
  
    /** Merges an array of TopGroups, for example obtained
     *  from the second-pass collector across multiple
     *  shards.  Each TopGroups must have been sorted by the
     *  same groupSort and docSort, and the top groups passed
     *  to all second-pass collectors must be the same.
     *
     * <b>NOTE</b>: We can't always compute an exact totalGroupCount.
     * Documents belonging to a group may occur on more than
     * one shard and thus the merged totalGroupCount can be
     * higher than the actual totalGroupCount. In this case the
     * totalGroupCount represents a upper bound. If the documents
     * of one group do only reside in one shard then the
     * totalGroupCount is exact.
     *
     * <b>NOTE</b>: the topDocs in each GroupDocs is actually
     * an instance of TopDocsAndShards
     */
    public static <T> TopGroups<T> merge(TopGroups<T>[] shardGroups, Sort groupSort, Sort docSort, int docOffset, int docTopN)
      throws IOException {
  
      //System.out.println("TopGroups.merge");
  
      if (shardGroups.length == 0) {
        return null;
      }
      HashMap<T, Integer> map = new HashMap<T, Integer>();
      int totalHitCount = 0;
      int totalGroupedHitCount = 0;
      // Optionally merge the totalGroupCount.
      Integer totalGroupCount = null;
  
      final int numGroups = shardGroups[0].groups.length;
      for(TopGroups<T> shard : shardGroups) {
        if (numGroups != shard.groups.length) {
          throw new IllegalArgumentException("number of groups differs across shards; you must pass same top groups to all shards' second-pass collector");
        }
        totalHitCount += shard.totalHitCount;
        totalGroupedHitCount += shard.totalGroupedHitCount;
        if (shard.totalGroupCount != null) {
          if (totalGroupCount == null) {
            totalGroupCount = 0;
          }
  
          totalGroupCount += shard.totalGroupCount;
        }
      }
  
      @SuppressWarnings("unchecked")
      final GroupDocs<T>[] mergedGroupDocs = new GroupDocs[numGroups];
  
      final TopDocs[] shardTopDocs = new TopDocs[shardGroups.length];
  
      for(int groupIDX=0;groupIDX<numGroups;groupIDX++) {
        final T groupValue = shardGroups[0].groups[groupIDX].groupValue;
        //System.out.println("  merge groupValue=" + groupValue + " sortValues=" + Arrays.toString(shardGroups[0].groups[groupIDX].groupSortValues));
        float maxScore = Float.MIN_VALUE;
  	  double sum = 0.0f;
    	  double max = Double.NEGATIVE_INFINITY;
    	  double min = Double.POSITIVE_INFINITY;
        int totalHits = 0;
        for(int shardIDX=0;shardIDX<shardGroups.length;shardIDX++) {
          //System.out.println("    shard=" + shardIDX);
          final TopGroups<T> shard = shardGroups[shardIDX];
          final GroupDocs shardGroupDocs = shard.groups[groupIDX];
          if (groupValue == null) {
            if (shardGroupDocs.groupValue != null) {
              throw new IllegalArgumentException("group values differ across shards; you must pass same top groups to all shards' second-pass collector");
            }
          } else if (!groupValue.equals(shardGroupDocs.groupValue)) {
            throw new IllegalArgumentException("group values differ across shards; you must pass same top groups to all shards' second-pass collector");
          }
          //[2011-12-27]qinjian
          if(!map.containsKey(shardGroupDocs.groupValue))
          	map.put(shard.groups[groupIDX].groupValue, new Integer(shardGroupDocs.totalHits));
          else{
          	Integer v = map.get(shard.groups[groupIDX].groupValue);
          	v = Integer.valueOf(v.intValue() + shardGroupDocs.totalHits);
          }
          /*
          for(ScoreDoc sd : shardGroupDocs.scoreDocs) {
            System.out.println("      doc=" + sd.doc);
          }
          */
  
          shardTopDocs[shardIDX] = new TopDocs(shardGroupDocs.totalHits,
                                               shardGroupDocs.scoreDocs,
                                               shardGroupDocs.maxScore,
  											 shardGroupDocs.sum,
  											 shardGroupDocs.max,
  											 shardGroupDocs.min);
          maxScore = Math.max(maxScore, shardGroupDocs.maxScore);
  		sum += shardGroupDocs.sum;
  		max = Math.max(max, shardGroupDocs.max);
  		min = Math.min(min, shardGroupDocs.min);
          totalHits += shardGroupDocs.totalHits;
        }
  
        final TopDocs mergedTopDocs = TopDocs.merge(docSort, docOffset + docTopN, shardTopDocs);
  
        // Slice;
        final ScoreDoc[] mergedScoreDocs;
        if (docOffset == 0) {
          mergedScoreDocs = mergedTopDocs.scoreDocs;
        } else if (docOffset >= mergedTopDocs.scoreDocs.length) {
          mergedScoreDocs = new ScoreDoc[0];
        } else {
          mergedScoreDocs = new ScoreDoc[mergedTopDocs.scoreDocs.length - docOffset];
          System.arraycopy(mergedTopDocs.scoreDocs,
                           docOffset,
                           mergedScoreDocs,
                           0,
                           mergedTopDocs.scoreDocs.length - docOffset);
        }
        //System.out.println("SHARDS=" + Arrays.toString(mergedTopDocs.shardIndex));
        mergedGroupDocs[groupIDX] = new GroupDocs<T>(maxScore,
                                                     totalHits,
                                                     mergedScoreDocs,
                                                     groupValue,
                                                     shardGroups[0].groups[groupIDX].groupSortValues,
  												   sum, max, min);
      }
      /*for(T g :map.keySet()){
      	System.out.print(g);
      	System.out.print(":");
      	System.out.println(map.get(g));
      }*/
      //System.out.println(totalGroupCount);
      totalGroupCount = map.keySet().size();
      if (totalGroupCount != null) {
        TopGroups<T> result = new TopGroups<T>(groupSort.getSort(),
                                docSort == null ? null : docSort.getSort(),
                                totalHitCount,
                                totalGroupedHitCount,
                                mergedGroupDocs);
        return new TopGroups<T>(result, totalGroupCount);
      } else {
        return new TopGroups<T>(groupSort.getSort(),
                                docSort == null ? null : docSort.getSort(),
                                totalHitCount,
                                totalGroupedHitCount,
                                mergedGroupDocs);
      }
    }
  }
  