Package org.apache.lucene.facet

Class FacetsCollector

java.lang.Object

org.apache.lucene.search.Collector

org.apache.lucene.facet.FacetsCollector

public class FacetsCollector
extends Collector

Collects hits for subsequent faceting. Once you've run a search and collect hits into this, instantiate one of the Facets subclasses to do the facet counting. Use the search utility methods to perform an "ordinary" search but also collect into a Collector.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final class	FacetsCollector.MatchingDocs	Holds the documents that were matched in the AtomicReaderContext.

Constructor Summary

Constructors

Constructor	Description
FacetsCollector()	Default constructor
FacetsCollector(boolean keepScores)	Create this; if keepScores is true then a float[] is allocated to hold score of all hits.

Method Summary

Modifier and Type	Method	Description
final 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).
final void	collect(int doc)	Called once for every document matching a query, with the unbased document number.
final boolean	getKeepScores()	True if scores were saved.
List<FacetsCollector.MatchingDocs>	getMatchingDocs()	Returns the documents matched by the query, one FacetsCollector.MatchingDocs per visited segment.
static TopDocs	search(IndexSearcher searcher, Query q, int n, Collector fc)	Utility method, to search and also collect all hits into the provided Collector.
static TopDocs	search(IndexSearcher searcher, Query q, Filter filter, int n, Collector fc)	Utility method, to search and also collect all hits into the provided Collector.
static TopFieldDocs	search(IndexSearcher searcher, Query q, Filter filter, int n, Sort sort, boolean doDocScores, boolean doMaxScore, Collector fc)	Utility method, to search and also collect all hits into the provided Collector.
static TopFieldDocs	search(IndexSearcher searcher, Query q, Filter filter, int n, Sort sort, Collector fc)	Utility method, to search and also collect all hits into the provided Collector.
TopDocs	searchAfter(IndexSearcher searcher, ScoreDoc after, Query q, int n, Collector fc)	Utility method, to search and also collect all hits into the provided Collector.
static TopDocs	searchAfter(IndexSearcher searcher, ScoreDoc after, Query q, Filter filter, int n, Collector fc)	Utility method, to search and also collect all hits into the provided Collector.
static TopDocs	searchAfter(IndexSearcher searcher, ScoreDoc after, Query q, Filter filter, int n, Sort sort, boolean doDocScores, boolean doMaxScore, Collector fc)	Utility method, to search and also collect all hits into the provided Collector.
static TopDocs	searchAfter(IndexSearcher searcher, ScoreDoc after, Query q, Filter filter, int n, Sort sort, Collector fc)	Utility method, to search and also collect all hits into the provided Collector.
final void	setNextReader(AtomicReaderContext context)	Called before collecting from each AtomicReaderContext.
final void	setScorer(Scorer scorer)	Called before successive calls to Collector.collect(int).

Methods inherited from class java.lang.Object

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

Constructor Details

FacetsCollector

public FacetsCollector()

Default constructor

FacetsCollector

public FacetsCollector(boolean keepScores)

Create this; if keepScores is true then a float[] is allocated to hold score of all hits.

Method Details

getKeepScores

public final boolean getKeepScores()

True if scores were saved.

getMatchingDocs

public List<FacetsCollector.MatchingDocs> getMatchingDocs()

Returns the documents matched by the query, one FacetsCollector.MatchingDocs per visited segment.

acceptsDocsOutOfOrder

public final 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 final 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: The collection of the current segment can be terminated by throwing a CollectionTerminatedException. In this case, the last docs of the current AtomicReaderContext will be skipped and IndexSearcher will swallow the exception and continue collection with the next leaf.

Note: This is called in an inner search loop. For good search performance, implementations of this method should not call IndexSearcher.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

setScorer

public final 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

setNextReader

public final void setNextReader(AtomicReaderContext context)
                         throws IOException

Description copied from class: Collector

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

Specified by:

setNextReader in class Collector

Parameters:

context - next atomic reader context

Throws:

IOException

search

public static TopDocs search(IndexSearcher searcher,
 Query q,
 int n,
 Collector fc)
                      throws IOException

Utility method, to search and also collect all hits into the provided Collector.

Throws:

IOException

search

public static TopDocs search(IndexSearcher searcher,
 Query q,
 Filter filter,
 int n,
 Collector fc)
                      throws IOException

Utility method, to search and also collect all hits into the provided Collector.

Throws:

IOException

search

public static TopFieldDocs search(IndexSearcher searcher,
 Query q,
 Filter filter,
 int n,
 Sort sort,
 Collector fc)
                           throws IOException

Utility method, to search and also collect all hits into the provided Collector.

Throws:

IOException

search

public static TopFieldDocs search(IndexSearcher searcher,
 Query q,
 Filter filter,
 int n,
 Sort sort,
 boolean doDocScores,
 boolean doMaxScore,
 Collector fc)
                           throws IOException

Utility method, to search and also collect all hits into the provided Collector.

Throws:

IOException

searchAfter

public TopDocs searchAfter(IndexSearcher searcher,
 ScoreDoc after,
 Query q,
 int n,
 Collector fc)
                    throws IOException

Utility method, to search and also collect all hits into the provided Collector.

Throws:

IOException

searchAfter

public static TopDocs searchAfter(IndexSearcher searcher,
 ScoreDoc after,
 Query q,
 Filter filter,
 int n,
 Collector fc)
                           throws IOException

Utility method, to search and also collect all hits into the provided Collector.

Throws:

IOException

searchAfter

public static TopDocs searchAfter(IndexSearcher searcher,
 ScoreDoc after,
 Query q,
 Filter filter,
 int n,
 Sort sort,
 Collector fc)
                           throws IOException

Utility method, to search and also collect all hits into the provided Collector.

Throws:

IOException

searchAfter

public static TopDocs searchAfter(IndexSearcher searcher,
 ScoreDoc after,
 Query q,
 Filter filter,
 int n,
 Sort sort,
 boolean doDocScores,
 boolean doMaxScore,
 Collector fc)
                           throws IOException

Utility method, to search and also collect all hits into the provided Collector.

Throws:

IOException