Class CollapsingTopDocsCollector<T>
- java.lang.Object
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- org.apache.lucene.search.SimpleCollector
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- org.apache.lucene.search.grouping.FirstPassGroupingCollector<T>
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- org.apache.lucene.search.grouping.CollapsingTopDocsCollector<T>
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- All Implemented Interfaces:
org.apache.lucene.search.Collector
,org.apache.lucene.search.LeafCollector
public final class CollapsingTopDocsCollector<T> extends org.apache.lucene.search.grouping.FirstPassGroupingCollector<T>
A collector that groups documents based on field values and returnsCollapseTopFieldDocs
output. The collapsing is done in a single pass by selecting only the top sorted document per collapse key. The value used for the collapse key of each group can be found inCollapseTopFieldDocs.collapseValues
.
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Field Summary
Fields Modifier and Type Field Description protected java.lang.String
collapseField
protected org.apache.lucene.search.Scorer
scorer
protected org.apache.lucene.search.Sort
sort
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Method Summary
Modifier and Type Method Description void
collect(int doc)
static CollapsingTopDocsCollector<?>
createKeyword(java.lang.String collapseField, org.apache.lucene.search.Sort sort, int topN, boolean trackMaxScore)
Create a collapsing top docs collector on aSortedDocValues
field.static CollapsingTopDocsCollector<?>
createNumeric(java.lang.String collapseField, org.apache.lucene.search.Sort sort, int topN, boolean trackMaxScore)
Create a collapsing top docs collector on aNumericDocValues
field.CollapseTopFieldDocs
getTopDocs()
TransformFirstPassGroupingCollector.getTopGroups(int, boolean)
output inCollapseTopFieldDocs
.boolean
needsScores()
void
setScorer(org.apache.lucene.search.Scorer scorer)
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Method Detail
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getTopDocs
public CollapseTopFieldDocs getTopDocs() throws java.io.IOException
TransformFirstPassGroupingCollector.getTopGroups(int, boolean)
output inCollapseTopFieldDocs
. The collapsing needs only one pass so we can get the final top docs at the end of the first pass.- Throws:
java.io.IOException
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needsScores
public boolean needsScores()
- Specified by:
needsScores
in interfaceorg.apache.lucene.search.Collector
- Overrides:
needsScores
in classorg.apache.lucene.search.grouping.FirstPassGroupingCollector<T>
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setScorer
public void setScorer(org.apache.lucene.search.Scorer scorer) throws java.io.IOException
- Specified by:
setScorer
in interfaceorg.apache.lucene.search.LeafCollector
- Overrides:
setScorer
in classorg.apache.lucene.search.grouping.FirstPassGroupingCollector<T>
- Throws:
java.io.IOException
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collect
public void collect(int doc) throws java.io.IOException
- Specified by:
collect
in interfaceorg.apache.lucene.search.LeafCollector
- Overrides:
collect
in classorg.apache.lucene.search.grouping.FirstPassGroupingCollector<T>
- Throws:
java.io.IOException
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createNumeric
public static CollapsingTopDocsCollector<?> createNumeric(java.lang.String collapseField, org.apache.lucene.search.Sort sort, int topN, boolean trackMaxScore)
Create a collapsing top docs collector on aNumericDocValues
field. It accepts alsoSortedNumericDocValues
field but the collect will fail with anIllegalStateException
if a document contains more than one value for the field.- Parameters:
collapseField
- The sort field used to group documents.sort
- TheSort
used to sort the collapsed hits. The collapsing keeps only the top sorted document per collapsed key. This must be non-null, ie, if you want to groupSort by relevance use Sort.RELEVANCE.topN
- How many top groups to keep.
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createKeyword
public static CollapsingTopDocsCollector<?> createKeyword(java.lang.String collapseField, org.apache.lucene.search.Sort sort, int topN, boolean trackMaxScore)
Create a collapsing top docs collector on aSortedDocValues
field. It accepts alsoSortedSetDocValues
field but the collect will fail with anIllegalStateException
if a document contains more than one value for the field.- Parameters:
collapseField
- The sort field used to group documents.sort
- TheSort
used to sort the collapsed hits. The collapsing keeps only the top sorted document per collapsed key. This must be non-null, ie, if you want to groupSort by relevance use Sort.RELEVANCE.topN
- How many top groups to keep.
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