Class BlockGroupingCollector
- All Implemented Interfaces:
Collector
,LeafCollector
IndexWriter.addDocuments()
or IndexWriter.updateDocuments()
API.
This results in faster performance (~25% faster QPS) than the two-pass grouping collectors,
with the tradeoff being that the documents in each group must always be indexed as a block. This
collector also fills in TopGroups.totalGroupCount without requiring the separate AllGroupsCollector
. However, this collector does not fill in
the groupValue of each group; this field will always be null.
NOTE: this collector makes no effort to verify the docs were in fact indexed as a block, so it's up to you to ensure this was the case.
See org.apache.lucene.search.grouping
for more details including a full code example.
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionprivate final class
private static final class
private static class
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate int
private final FieldComparator<?>[]
private final int
private LeafReaderContext
private int
private boolean
private int
private final BlockGroupingCollector.GroupQueue
private final Sort
private final Weight
private DocIdSetIterator
private final LeafFieldComparator[]
private final boolean
private int[]
private float[]
private boolean
private final int[]
private Scorable
private int
private int
private final int
private int
private int
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Constructor Summary
ConstructorsConstructorDescriptionBlockGroupingCollector
(Sort groupSort, int topNGroups, boolean needsScores, Weight lastDocPerGroup) Create the single pass collector. -
Method Summary
Modifier and TypeMethodDescriptionvoid
collect
(int doc) Called once for every document matching a query, with the unbased document number.protected void
doSetNextReader
(LeafReaderContext readerContext) This method is called before collectingcontext
.TopGroups<?>
getTopGroups
(Sort withinGroupSort, int groupOffset, int withinGroupOffset, int maxDocsPerGroup) Returns the grouped results.private void
Indicates what features are required from the scorer.void
Called before successive calls toLeafCollector.collect(int)
.Methods inherited from class org.apache.lucene.search.SimpleCollector
getLeafCollector
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Methods inherited from interface org.apache.lucene.search.LeafCollector
competitiveIterator
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Field Details
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pendingSubDocs
private int[] pendingSubDocs -
pendingSubScores
private float[] pendingSubScores -
subDocUpto
private int subDocUpto -
groupSort
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topNGroups
private final int topNGroups -
lastDocPerGroup
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needsScores
private final boolean needsScores -
comparators
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leafComparators
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reversed
private final int[] reversed -
compIDXEnd
private final int compIDXEnd -
bottomSlot
private int bottomSlot -
queueFull
private boolean queueFull -
currentReaderContext
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topGroupDoc
private int topGroupDoc -
totalHitCount
private int totalHitCount -
totalGroupCount
private int totalGroupCount -
docBase
private int docBase -
groupEndDocID
private int groupEndDocID -
lastDocPerGroupBits
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scorer
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groupQueue
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groupCompetes
private boolean groupCompetes
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Constructor Details
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BlockGroupingCollector
public BlockGroupingCollector(Sort groupSort, int topNGroups, boolean needsScores, Weight lastDocPerGroup) Create the single pass collector.- Parameters:
groupSort
- TheSort
used to sort the groups. The top sorted document within each group according to groupSort, determines how that group sorts against other groups. This must be non-null, ie, if you want to groupSort by relevance use Sort.RELEVANCE.topNGroups
- How many top groups to keep.needsScores
- true if the collected documents require scores, either because relevance is included in the withinGroupSort or because you plan to pass true for either getSscores or getMaxScores togetTopGroups(org.apache.lucene.search.Sort, int, int, int)
lastDocPerGroup
- aWeight
that marks the last document in each group.
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Method Details
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processGroup
- Throws:
IOException
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getTopGroups
public TopGroups<?> getTopGroups(Sort withinGroupSort, int groupOffset, int withinGroupOffset, int maxDocsPerGroup) throws IOException Returns the grouped results. Returns null if the number of groups collected is <= groupOffset.NOTE: This collector is unable to compute the groupValue per group so it will always be null. This is normally not a problem, as you can obtain the value just like you obtain other values for each matching document (eg, via stored fields, via DocValues, etc.)
- Parameters:
withinGroupSort
- TheSort
used to sort documents within each group.groupOffset
- Which group to start fromwithinGroupOffset
- Which document to start from within each groupmaxDocsPerGroup
- How many top documents to keep within each group.- Throws:
IOException
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setScorer
Description copied from interface:LeafCollector
Called before successive calls toLeafCollector.collect(int)
. Implementations that need the score of the current document (passed-in toLeafCollector.collect(int)
), should save the passed-in Scorer and call scorer.score() when needed.- Specified by:
setScorer
in interfaceLeafCollector
- Overrides:
setScorer
in classSimpleCollector
- Throws:
IOException
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collect
Description copied from interface:LeafCollector
Called once for every document matching a query, with the unbased document number.Note: The collection of the current segment can be terminated by throwing a
CollectionTerminatedException
. In this case, the last docs of the currentLeafReaderContext
will be skipped andIndexSearcher
will swallow the exception and continue collection with the next leaf.Note: This is called in an inner search loop. For good search performance, implementations of this method should not call
StoredFields.document(int)
on every hit. Doing so can slow searches by an order of magnitude or more.- Specified by:
collect
in interfaceLeafCollector
- Specified by:
collect
in classSimpleCollector
- Throws:
IOException
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doSetNextReader
Description copied from class:SimpleCollector
This method is called before collectingcontext
.- Overrides:
doSetNextReader
in classSimpleCollector
- Throws:
IOException
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scoreMode
Description copied from interface:Collector
Indicates what features are required from the scorer.
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