Class AbstractSecondPassGroupingCollector<GROUP_VALUE_TYPE>
- java.lang.Object
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- org.apache.lucene.search.Collector
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- org.apache.lucene.search.grouping.AbstractSecondPassGroupingCollector<GROUP_VALUE_TYPE>
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- Direct Known Subclasses:
TermSecondPassGroupingCollector
public abstract class AbstractSecondPassGroupingCollector<GROUP_VALUE_TYPE> extends Collector
SecondPassGroupingCollector is the second of two passes necessary to collect grouped docs. This pass gathers the top N documents per top group computed from the first pass. Concrete subclasses define what a group is and how it is internally collected.See
org.apache.lucene.search.grouping
for more details including a full code example.- WARNING: This API is experimental and might change in incompatible ways in the next release.
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Nested Class Summary
Nested Classes Modifier and Type Class Description class
AbstractSecondPassGroupingCollector.SearchGroupDocs<GROUP_VALUE_TYPE>
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Field Summary
Fields Modifier and Type Field Description protected AbstractSecondPassGroupingCollector.SearchGroupDocs<GROUP_VALUE_TYPE>[]
groupDocs
protected Map<GROUP_VALUE_TYPE,AbstractSecondPassGroupingCollector.SearchGroupDocs<GROUP_VALUE_TYPE>>
groupMap
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Constructor Summary
Constructors Constructor Description AbstractSecondPassGroupingCollector(Collection<SearchGroup<GROUP_VALUE_TYPE>> groups, Sort groupSort, Sort withinGroupSort, int maxDocsPerGroup, boolean getScores, boolean getMaxScores, boolean fillSortFields)
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description boolean
acceptsDocsOutOfOrder()
Returntrue
if this collector does not require the matching docIDs to be delivered in int sort order (smallest to largest) toCollector.collect(int)
.void
collect(int doc)
Called once for every document matching a query, with the unbased document number.TopGroups<GROUP_VALUE_TYPE>
getTopGroups(int withinGroupOffset)
protected abstract AbstractSecondPassGroupingCollector.SearchGroupDocs<GROUP_VALUE_TYPE>
retrieveGroup(int doc)
Returns the group the specified doc belongs to ornull
if no group could be retrieved.void
setNextReader(IndexReader reader, int docBase)
Called before collecting from each IndexReader.void
setScorer(Scorer scorer)
Called before successive calls toCollector.collect(int)
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Field Detail
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groupMap
protected final Map<GROUP_VALUE_TYPE,AbstractSecondPassGroupingCollector.SearchGroupDocs<GROUP_VALUE_TYPE>> groupMap
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groupDocs
protected AbstractSecondPassGroupingCollector.SearchGroupDocs<GROUP_VALUE_TYPE>[] groupDocs
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Constructor Detail
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AbstractSecondPassGroupingCollector
public AbstractSecondPassGroupingCollector(Collection<SearchGroup<GROUP_VALUE_TYPE>> groups, Sort groupSort, Sort withinGroupSort, int maxDocsPerGroup, boolean getScores, boolean getMaxScores, boolean fillSortFields) throws IOException
- Throws:
IOException
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Method Detail
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setScorer
public void setScorer(Scorer scorer) throws IOException
Description copied from class:Collector
Called before successive calls toCollector.collect(int)
. Implementations that need the score of the current document (passed-in toCollector.collect(int)
), should save the passed-in Scorer and call scorer.score() when needed.- Specified by:
setScorer
in classCollector
- Throws:
IOException
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collect
public void collect(int doc) throws IOException
Description copied from class:Collector
Called once for every document matching a query, with the unbased document number.Note: This is called in an inner search loop. For good search performance, implementations of this method should not call
Searcher.doc(int)
orIndexReader.document(int)
on every hit. Doing so can slow searches by an order of magnitude or more.- Specified by:
collect
in classCollector
- Throws:
IOException
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retrieveGroup
protected abstract AbstractSecondPassGroupingCollector.SearchGroupDocs<GROUP_VALUE_TYPE> retrieveGroup(int doc) throws IOException
Returns the group the specified doc belongs to ornull
if no group could be retrieved.- Parameters:
doc
- The specified doc- Returns:
- the group the specified doc belongs to or
null
if no group could be retrieved - Throws:
IOException
- If an I/O related error occurred
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setNextReader
public void setNextReader(IndexReader reader, int docBase) throws IOException
Description copied from class:Collector
Called before collecting from each IndexReader. All doc ids inCollector.collect(int)
will correspond to reader. Add docBase to the current IndexReaders internal document id to re-base ids inCollector.collect(int)
.- Specified by:
setNextReader
in classCollector
- Parameters:
reader
- next IndexReader- Throws:
IOException
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acceptsDocsOutOfOrder
public boolean acceptsDocsOutOfOrder()
Description copied from class:Collector
Returntrue
if this collector does not require the matching docIDs to be delivered in int sort order (smallest to largest) toCollector.collect(int)
.Most Lucene Query implementations will visit matching docIDs in order. However, some queries (currently limited to certain cases of
BooleanQuery
) can achieve faster searching if theCollector
allows them to deliver the docIDs out of order.Many collectors don't mind getting docIDs out of order, so it's important to return
true
here.- Specified by:
acceptsDocsOutOfOrder
in classCollector
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getTopGroups
public TopGroups<GROUP_VALUE_TYPE> getTopGroups(int withinGroupOffset)
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