http://lucene.apache.org/lucene-parent/lucene-grouping: Lucene Grouping Module (The Apache Software Foundation) 
public abstract class org.apache.lucene.search.grouping.GroupFacetCollector extends org.apache.lucene.search.SimpleCollector
  minor version: 0
  major version: 59
  flags: flags: (0x0421) ACC_PUBLIC, ACC_SUPER, ACC_ABSTRACT
  this_class: org.apache.lucene.search.grouping.GroupFacetCollector
  super_class: org.apache.lucene.search.SimpleCollector
{
  protected final java.lang.String groupField;
    descriptor: Ljava/lang/String;
    flags: (0x0014) ACC_PROTECTED, ACC_FINAL

  protected final java.lang.String facetField;
    descriptor: Ljava/lang/String;
    flags: (0x0014) ACC_PROTECTED, ACC_FINAL

  protected final org.apache.lucene.util.BytesRef facetPrefix;
    descriptor: Lorg/apache/lucene/util/BytesRef;
    flags: (0x0014) ACC_PROTECTED, ACC_FINAL

  protected final java.util.List<org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResult> segmentResults;
    descriptor: Ljava/util/List;
    flags: (0x0014) ACC_PROTECTED, ACC_FINAL
    Signature: Ljava/util/List<Lorg/apache/lucene/search/grouping/GroupFacetCollector$SegmentResult;>;

  protected int[] segmentFacetCounts;
    descriptor: [I
    flags: (0x0004) ACC_PROTECTED

  protected int segmentTotalCount;
    descriptor: I
    flags: (0x0004) ACC_PROTECTED

  protected int startFacetOrd;
    descriptor: I
    flags: (0x0004) ACC_PROTECTED

  protected int endFacetOrd;
    descriptor: I
    flags: (0x0004) ACC_PROTECTED

  protected void <init>(java.lang.String, java.lang.String, org.apache.lucene.util.BytesRef);
    descriptor: (Ljava/lang/String;Ljava/lang/String;Lorg/apache/lucene/util/BytesRef;)V
    flags: (0x0004) ACC_PROTECTED
    Code:
      stack=3, locals=4, args_size=4
        start local 0 // org.apache.lucene.search.grouping.GroupFacetCollector this
        start local 1 // java.lang.String groupField
        start local 2 // java.lang.String facetField
        start local 3 // org.apache.lucene.util.BytesRef facetPrefix
         0: .line 50
            aload 0 /* this */
            invokespecial org.apache.lucene.search.SimpleCollector.<init>:()V
         1: .line 51
            aload 0 /* this */
            aload 1 /* groupField */
            putfield org.apache.lucene.search.grouping.GroupFacetCollector.groupField:Ljava/lang/String;
         2: .line 52
            aload 0 /* this */
            aload 2 /* facetField */
            putfield org.apache.lucene.search.grouping.GroupFacetCollector.facetField:Ljava/lang/String;
         3: .line 53
            aload 0 /* this */
            aload 3 /* facetPrefix */
            putfield org.apache.lucene.search.grouping.GroupFacetCollector.facetPrefix:Lorg/apache/lucene/util/BytesRef;
         4: .line 54
            aload 0 /* this */
            new java.util.ArrayList
            dup
            invokespecial java.util.ArrayList.<init>:()V
            putfield org.apache.lucene.search.grouping.GroupFacetCollector.segmentResults:Ljava/util/List;
         5: .line 55
            return
        end local 3 // org.apache.lucene.util.BytesRef facetPrefix
        end local 2 // java.lang.String facetField
        end local 1 // java.lang.String groupField
        end local 0 // org.apache.lucene.search.grouping.GroupFacetCollector this
      LocalVariableTable:
        Start  End  Slot         Name  Signature
            0    6     0         this  Lorg/apache/lucene/search/grouping/GroupFacetCollector;
            0    6     1   groupField  Ljava/lang/String;
            0    6     2   facetField  Ljava/lang/String;
            0    6     3  facetPrefix  Lorg/apache/lucene/util/BytesRef;
    MethodParameters:
             Name  Flags
      groupField   
      facetField   
      facetPrefix  

  public org.apache.lucene.search.grouping.GroupFacetCollector$GroupedFacetResult mergeSegmentResults(int, int, boolean);
    descriptor: (IIZ)Lorg/apache/lucene/search/grouping/GroupFacetCollector$GroupedFacetResult;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=7, locals=11, args_size=4
        start local 0 // org.apache.lucene.search.grouping.GroupFacetCollector this
        start local 1 // int size
        start local 2 // int minCount
        start local 3 // boolean orderByCount
         0: .line 69
            aload 0 /* this */
            getfield org.apache.lucene.search.grouping.GroupFacetCollector.segmentFacetCounts:[I
            ifnull 3
         1: .line 70
            aload 0 /* this */
            getfield org.apache.lucene.search.grouping.GroupFacetCollector.segmentResults:Ljava/util/List;
            aload 0 /* this */
            invokevirtual org.apache.lucene.search.grouping.GroupFacetCollector.createSegmentResult:()Lorg/apache/lucene/search/grouping/GroupFacetCollector$SegmentResult;
            invokeinterface java.util.List.add:(Ljava/lang/Object;)Z
            pop
         2: .line 71
            aload 0 /* this */
            aconst_null
            putfield org.apache.lucene.search.grouping.GroupFacetCollector.segmentFacetCounts:[I
         3: .line 74
      StackMap locals:
      StackMap stack:
            iconst_0
            istore 4 /* totalCount */
        start local 4 // int totalCount
         4: .line 75
            iconst_0
            istore 5 /* missingCount */
        start local 5 // int missingCount
         5: .line 76
            new org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResultPriorityQueue
            dup
            aload 0 /* this */
            getfield org.apache.lucene.search.grouping.GroupFacetCollector.segmentResults:Ljava/util/List;
            invokeinterface java.util.List.size:()I
            invokespecial org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResultPriorityQueue.<init>:(I)V
            astore 6 /* segments */
        start local 6 // org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResultPriorityQueue segments
         6: .line 77
            aload 0 /* this */
            getfield org.apache.lucene.search.grouping.GroupFacetCollector.segmentResults:Ljava/util/List;
            invokeinterface java.util.List.iterator:()Ljava/util/Iterator;
            astore 8
            goto 13
      StackMap locals: org.apache.lucene.search.grouping.GroupFacetCollector int int int int int org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResultPriorityQueue top java.util.Iterator
      StackMap stack:
         7: aload 8
            invokeinterface java.util.Iterator.next:()Ljava/lang/Object;
            checkcast org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResult
            astore 7 /* segmentResult */
        start local 7 // org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResult segmentResult
         8: .line 78
            iload 5 /* missingCount */
            aload 7 /* segmentResult */
            getfield org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResult.missing:I
            iadd
            istore 5 /* missingCount */
         9: .line 79
            aload 7 /* segmentResult */
            getfield org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResult.mergePos:I
            aload 7 /* segmentResult */
            getfield org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResult.maxTermPos:I
            if_icmplt 11
        10: .line 80
            goto 13
        11: .line 82
      StackMap locals: org.apache.lucene.search.grouping.GroupFacetCollector int int int int int org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResultPriorityQueue org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResult java.util.Iterator
      StackMap stack:
            iload 4 /* totalCount */
            aload 7 /* segmentResult */
            getfield org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResult.total:I
            iadd
            istore 4 /* totalCount */
        12: .line 83
            aload 6 /* segments */
            aload 7 /* segmentResult */
            invokevirtual org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResultPriorityQueue.add:(Ljava/lang/Object;)Ljava/lang/Object;
            pop
        end local 7 // org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResult segmentResult
        13: .line 77
      StackMap locals: org.apache.lucene.search.grouping.GroupFacetCollector int int int int int org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResultPriorityQueue top java.util.Iterator
      StackMap stack:
            aload 8
            invokeinterface java.util.Iterator.hasNext:()Z
            ifne 7
        14: .line 86
            new org.apache.lucene.search.grouping.GroupFacetCollector$GroupedFacetResult
            dup
            iload 1 /* size */
            iload 2 /* minCount */
            iload 3 /* orderByCount */
            iload 4 /* totalCount */
            iload 5 /* missingCount */
            invokespecial org.apache.lucene.search.grouping.GroupFacetCollector$GroupedFacetResult.<init>:(IIZII)V
            astore 7 /* facetResult */
        start local 7 // org.apache.lucene.search.grouping.GroupFacetCollector$GroupedFacetResult facetResult
        15: .line 87
            goto 30
        16: .line 88
      StackMap locals: org.apache.lucene.search.grouping.GroupFacetCollector int int int int int org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResultPriorityQueue org.apache.lucene.search.grouping.GroupFacetCollector$GroupedFacetResult
      StackMap stack:
            aload 6 /* segments */
            invokevirtual org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResultPriorityQueue.top:()Ljava/lang/Object;
            checkcast org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResult
            astore 8 /* segmentResult */
        start local 8 // org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResult segmentResult
        17: .line 89
            aload 8 /* segmentResult */
            getfield org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResult.mergeTerm:Lorg/apache/lucene/util/BytesRef;
            invokestatic org.apache.lucene.util.BytesRef.deepCopyOf:(Lorg/apache/lucene/util/BytesRef;)Lorg/apache/lucene/util/BytesRef;
            astore 9 /* currentFacetValue */
        start local 9 // org.apache.lucene.util.BytesRef currentFacetValue
        18: .line 90
            iconst_0
            istore 10 /* count */
        start local 10 // int count
        19: .line 93
      StackMap locals: org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResult org.apache.lucene.util.BytesRef int
      StackMap stack:
            iload 10 /* count */
            aload 8 /* segmentResult */
            getfield org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResult.counts:[I
            aload 8 /* segmentResult */
            dup
            getfield org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResult.mergePos:I
            dup_x1
            iconst_1
            iadd
            putfield org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResult.mergePos:I
            iaload
            iadd
            istore 10 /* count */
        20: .line 94
            aload 8 /* segmentResult */
            getfield org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResult.mergePos:I
            aload 8 /* segmentResult */
            getfield org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResult.maxTermPos:I
            if_icmpge 24
        21: .line 95
            aload 8 /* segmentResult */
            invokevirtual org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResult.nextTerm:()V
        22: .line 96
            aload 6 /* segments */
            invokevirtual org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResultPriorityQueue.updateTop:()Ljava/lang/Object;
            checkcast org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResult
            astore 8 /* segmentResult */
        23: .line 97
            goto 28
        24: .line 98
      StackMap locals:
      StackMap stack:
            aload 6 /* segments */
            invokevirtual org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResultPriorityQueue.pop:()Ljava/lang/Object;
            pop
        25: .line 99
            aload 6 /* segments */
            invokevirtual org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResultPriorityQueue.top:()Ljava/lang/Object;
            checkcast org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResult
            astore 8 /* segmentResult */
        26: .line 100
            aload 8 /* segmentResult */
            ifnonnull 28
        27: .line 101
            goto 29
        28: .line 104
      StackMap locals:
      StackMap stack:
            aload 9 /* currentFacetValue */
            aload 8 /* segmentResult */
            getfield org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResult.mergeTerm:Lorg/apache/lucene/util/BytesRef;
            invokevirtual org.apache.lucene.util.BytesRef.equals:(Ljava/lang/Object;)Z
            ifne 19
        29: .line 105
      StackMap locals:
      StackMap stack:
            aload 7 /* facetResult */
            aload 9 /* currentFacetValue */
            iload 10 /* count */
            invokevirtual org.apache.lucene.search.grouping.GroupFacetCollector$GroupedFacetResult.addFacetCount:(Lorg/apache/lucene/util/BytesRef;I)V
        end local 10 // int count
        end local 9 // org.apache.lucene.util.BytesRef currentFacetValue
        end local 8 // org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResult segmentResult
        30: .line 87
      StackMap locals:
      StackMap stack:
            aload 6 /* segments */
            invokevirtual org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResultPriorityQueue.size:()I
            ifgt 16
        31: .line 107
            aload 7 /* facetResult */
            areturn
        end local 7 // org.apache.lucene.search.grouping.GroupFacetCollector$GroupedFacetResult facetResult
        end local 6 // org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResultPriorityQueue segments
        end local 5 // int missingCount
        end local 4 // int totalCount
        end local 3 // boolean orderByCount
        end local 2 // int minCount
        end local 1 // int size
        end local 0 // org.apache.lucene.search.grouping.GroupFacetCollector this
      LocalVariableTable:
        Start  End  Slot               Name  Signature
            0   32     0               this  Lorg/apache/lucene/search/grouping/GroupFacetCollector;
            0   32     1               size  I
            0   32     2           minCount  I
            0   32     3       orderByCount  Z
            4   32     4         totalCount  I
            5   32     5       missingCount  I
            6   32     6           segments  Lorg/apache/lucene/search/grouping/GroupFacetCollector$SegmentResultPriorityQueue;
            8   13     7      segmentResult  Lorg/apache/lucene/search/grouping/GroupFacetCollector$SegmentResult;
           15   32     7        facetResult  Lorg/apache/lucene/search/grouping/GroupFacetCollector$GroupedFacetResult;
           17   30     8      segmentResult  Lorg/apache/lucene/search/grouping/GroupFacetCollector$SegmentResult;
           18   30     9  currentFacetValue  Lorg/apache/lucene/util/BytesRef;
           19   30    10              count  I
    Exceptions:
      throws java.io.IOException
    MethodParameters:
              Name  Flags
      size          
      minCount      
      orderByCount  

  protected abstract org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResult createSegmentResult();
    descriptor: ()Lorg/apache/lucene/search/grouping/GroupFacetCollector$SegmentResult;
    flags: (0x0404) ACC_PROTECTED, ACC_ABSTRACT
    Exceptions:
      throws java.io.IOException

  public void setScorer(org.apache.lucene.search.Scorable);
    descriptor: (Lorg/apache/lucene/search/Scorable;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=0, locals=2, args_size=2
        start local 0 // org.apache.lucene.search.grouping.GroupFacetCollector this
        start local 1 // org.apache.lucene.search.Scorable scorer
         0: .line 114
            return
        end local 1 // org.apache.lucene.search.Scorable scorer
        end local 0 // org.apache.lucene.search.grouping.GroupFacetCollector this
      LocalVariableTable:
        Start  End  Slot    Name  Signature
            0    1     0    this  Lorg/apache/lucene/search/grouping/GroupFacetCollector;
            0    1     1  scorer  Lorg/apache/lucene/search/Scorable;
    Exceptions:
      throws java.io.IOException
    MethodParameters:
        Name  Flags
      scorer  

  public org.apache.lucene.search.ScoreMode scoreMode();
    descriptor: ()Lorg/apache/lucene/search/ScoreMode;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // org.apache.lucene.search.grouping.GroupFacetCollector this
         0: .line 118
            getstatic org.apache.lucene.search.ScoreMode.COMPLETE_NO_SCORES:Lorg/apache/lucene/search/ScoreMode;
            areturn
        end local 0 // org.apache.lucene.search.grouping.GroupFacetCollector this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lorg/apache/lucene/search/grouping/GroupFacetCollector;
}
SourceFile: "GroupFacetCollector.java"
NestMembers:
  org.apache.lucene.search.grouping.GroupFacetCollector$FacetEntry  org.apache.lucene.search.grouping.GroupFacetCollector$GroupedFacetResult  org.apache.lucene.search.grouping.GroupFacetCollector$GroupedFacetResult$1  org.apache.lucene.search.grouping.GroupFacetCollector$GroupedFacetResult$2  org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResult  org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResultPriorityQueue
InnerClasses:
  public FacetEntry = org.apache.lucene.search.grouping.GroupFacetCollector$FacetEntry of org.apache.lucene.search.grouping.GroupFacetCollector
  public GroupedFacetResult = org.apache.lucene.search.grouping.GroupFacetCollector$GroupedFacetResult of org.apache.lucene.search.grouping.GroupFacetCollector
  protected abstract SegmentResult = org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResult of org.apache.lucene.search.grouping.GroupFacetCollector
  private SegmentResultPriorityQueue = org.apache.lucene.search.grouping.GroupFacetCollector$SegmentResultPriorityQueue of org.apache.lucene.search.grouping.GroupFacetCollector