Package org.apache.lucene.facet.search
Class FacetsCollector
- java.lang.Object
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- org.apache.lucene.search.Collector
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- org.apache.lucene.facet.search.FacetsCollector
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public class FacetsCollector extends Collector
Collector for facet accumulation. *- WARNING: This API is experimental and might change in incompatible ways in the next release.
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Field Summary
Fields Modifier and Type Field Description protected FacetsAccumulator
facetsAccumulator
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Constructor Summary
Constructors Constructor Description FacetsCollector(FacetSearchParams facetSearchParams, IndexReader indexReader, TaxonomyReader taxonomyReader)
Create a collector for accumulating facets while collecting documents during search.
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Method Summary
All Methods Instance 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.List<FacetResult>
getFacetResults()
Return accumulated facets results (according to faceted search parameters) for collected documents.protected FacetsAccumulator
initFacetsAccumulator(FacetSearchParams facetSearchParams, IndexReader indexReader, TaxonomyReader taxonomyReader)
Create theFacetsAccumulator
to be used.protected ScoredDocIdCollector
initScoredDocCollector(FacetSearchParams facetSearchParams, IndexReader indexReader, TaxonomyReader taxonomyReader)
Create aScoredDocIdCollector
to be used as the first phase of the facet collection.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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facetsAccumulator
protected final FacetsAccumulator facetsAccumulator
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Constructor Detail
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FacetsCollector
public FacetsCollector(FacetSearchParams facetSearchParams, IndexReader indexReader, TaxonomyReader taxonomyReader)
Create a collector for accumulating facets while collecting documents during search.- Parameters:
facetSearchParams
- faceted search parameters defining which facets are required and how.indexReader
- searched index.taxonomyReader
- taxonomy containing the facets.
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Method Detail
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initScoredDocCollector
protected ScoredDocIdCollector initScoredDocCollector(FacetSearchParams facetSearchParams, IndexReader indexReader, TaxonomyReader taxonomyReader)
Create aScoredDocIdCollector
to be used as the first phase of the facet collection. If all facetRequests are do not require the document score, a ScoredDocIdCollector which does not store the document scores would be returned. Otherwise a SDIC which does store the documents will be returned, having an initial allocated space for 1000 such documents' scores.
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initFacetsAccumulator
protected FacetsAccumulator initFacetsAccumulator(FacetSearchParams facetSearchParams, IndexReader indexReader, TaxonomyReader taxonomyReader)
Create theFacetsAccumulator
to be used. Default isStandardFacetsAccumulator
. Called once at the constructor of the collector.- Parameters:
facetSearchParams
- The search params.indexReader
- A reader to the index to search in.taxonomyReader
- A reader to the active taxonomy.- Returns:
- The
FacetsAccumulator
to use.
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getFacetResults
public List<FacetResult> getFacetResults() throws IOException
Return accumulated facets results (according to faceted search parameters) for collected documents.- Throws:
IOException
- on error
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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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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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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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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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