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 FacetsAccumulatorfacetsAccumulator
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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 booleanacceptsDocsOutOfOrder()Returntrueif this collector does not require the matching docIDs to be delivered in int sort order (smallest to largest) toCollector.collect(int).voidcollect(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 FacetsAccumulatorinitFacetsAccumulator(FacetSearchParams facetSearchParams, IndexReader indexReader, TaxonomyReader taxonomyReader)Create theFacetsAccumulatorto be used.protected ScoredDocIdCollectorinitScoredDocCollector(FacetSearchParams facetSearchParams, IndexReader indexReader, TaxonomyReader taxonomyReader)Create aScoredDocIdCollectorto be used as the first phase of the facet collection.voidsetNextReader(IndexReader reader, int docBase)Called before collecting from each IndexReader.voidsetScorer(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 aScoredDocIdCollectorto 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 theFacetsAccumulatorto 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
FacetsAccumulatorto 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:CollectorReturntrueif 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 theCollectorallows them to deliver the docIDs out of order.Many collectors don't mind getting docIDs out of order, so it's important to return
truehere.- Specified by:
acceptsDocsOutOfOrderin classCollector
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collect
public void collect(int doc) throws IOExceptionDescription copied from class:CollectorCalled 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:
collectin classCollector- Throws:
IOException
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setNextReader
public void setNextReader(IndexReader reader, int docBase) throws IOException
Description copied from class:CollectorCalled 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:
setNextReaderin classCollector- Parameters:
reader- next IndexReader- Throws:
IOException
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setScorer
public void setScorer(Scorer scorer) throws IOException
Description copied from class:CollectorCalled 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:
setScorerin classCollector- Throws:
IOException
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