org.apache.lucene.facet.search
Class FacetsCollector

java.lang.Object
  org.apache.lucene.search.Collector
      org.apache.lucene.facet.search.FacetsCollector

public class FacetsCollector
extends Collector

Collector for facet accumulation. *

WARNING: This API is experimental and might change in incompatible ways in the next release.

Field Summary

protected FacetsAccumulator

facetsAccumulator

Constructor Summary

FacetsCollector(FacetSearchParams facetSearchParams, IndexReader indexReader, TaxonomyReader taxonomyReader)
Create a collector for accumulating facets while collecting documents during search.

Method Summary

boolean	acceptsDocsOutOfOrder() Return true if this collector does not require the matching docIDs to be delivered in int sort order (smallest to largest) to Collector.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 the FacetsAccumulator to be used.
protected ScoredDocIdCollector	initScoredDocCollector(FacetSearchParams facetSearchParams, IndexReader indexReader, TaxonomyReader taxonomyReader) Create a ScoredDocIdCollector 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 to Collector.collect(int).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

facetsAccumulator

protected final FacetsAccumulator facetsAccumulator

Constructor Detail

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.

Method Detail

initScoredDocCollector

protected ScoredDocIdCollector initScoredDocCollector(FacetSearchParams facetSearchParams,
                                                      IndexReader indexReader,
                                                      TaxonomyReader taxonomyReader)

Create a ScoredDocIdCollector 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.

initFacetsAccumulator

protected FacetsAccumulator initFacetsAccumulator(FacetSearchParams facetSearchParams,
                                                  IndexReader indexReader,
                                                  TaxonomyReader taxonomyReader)

Create the FacetsAccumulator to be used. Default is StandardFacetsAccumulator. 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.

getFacetResults

public List<FacetResult> getFacetResults()
                                  throws IOException

Return accumulated facets results (according to faceted search parameters) for collected documents.

Throws:

IOException - on error

acceptsDocsOutOfOrder

public boolean acceptsDocsOutOfOrder()

Description copied from class: Collector

Return true if this collector does not require the matching docIDs to be delivered in int sort order (smallest to largest) to Collector.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 the Collector 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 class Collector

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) or IndexReader.document(int) on every hit. Doing so can slow searches by an order of magnitude or more.

Specified by:

collect in class Collector

Throws:

IOException

setNextReader

public void setNextReader(IndexReader reader,
                          int docBase)
                   throws IOException

Description copied from class: Collector

Called before collecting from each IndexReader. All doc ids in Collector.collect(int) will correspond to reader. Add docBase to the current IndexReaders internal document id to re-base ids in Collector.collect(int).

Specified by:

setNextReader in class Collector

Parameters:

reader - next IndexReader

Throws:

IOException

setScorer

public void setScorer(Scorer scorer)
               throws IOException

Description copied from class: Collector

Called before successive calls to Collector.collect(int). Implementations that need the score of the current document (passed-in to Collector.collect(int)), should save the passed-in Scorer and call scorer.score() when needed.

Specified by:

setScorer in class Collector

Throws:

IOException