org.apache.lucene.search

Class ScoreCachingWrappingScorer

java.lang.Object

org.apache.lucene.search.Scorer

org.apache.lucene.search.FilterScorer

org.apache.lucene.search.ScoreCachingWrappingScorer

public class ScoreCachingWrappingScorer
extends FilterScorer

A Scorer which wraps another scorer and caches the score of the current document. Successive calls to score() will return the same result and will not invoke the wrapped Scorer's score() method, unless the current document has changed.
This class might be useful due to the changes done to the Collector interface, in which the score is not computed for a document by default, only if the collector requests it. Some collectors may need to use the score in several places, however all they have in hand is a Scorer object, and might end up computing the score of a document more than once.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.lucene.search.Scorer

Scorer.ChildScorer

Field Summary

Fields inherited from class org.apache.lucene.search.FilterScorer

in

Fields inherited from class org.apache.lucene.search.Scorer

weight

Constructor Summary

Constructors

Constructor and Description
ScoreCachingWrappingScorer(Scorer scorer) Creates a new instance by wrapping the given scorer.

Method Summary

Modifier and Type	Method and Description
Collection<Scorer.ChildScorer>	getChildren() Returns child sub-scorers positioned on the current document Note that this method should not be called on Scorers passed to LeafCollector.setScorer(Scorer), as these may be synthetic Scorers produced by BulkScorer which will throw an Exception.
float	score() Returns the score of the current document matching the query.

Methods inherited from class org.apache.lucene.search.FilterScorer

docID, iterator, twoPhaseIterator

Methods inherited from class org.apache.lucene.search.Scorer

getWeight

Methods inherited from class java.lang.Object

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

Constructor Detail

ScoreCachingWrappingScorer

public ScoreCachingWrappingScorer(Scorer scorer)

Creates a new instance by wrapping the given scorer.

Method Detail

score

public float score()
            throws IOException

Description copied from class: Scorer

Returns the score of the current document matching the query. Initially invalid, until DocIdSetIterator.nextDoc() or DocIdSetIterator.advance(int) is called on the Scorer.iterator() the first time, or when called from within LeafCollector.collect(int).

Overrides:

score in class FilterScorer

Throws:

IOException

getChildren

public Collection<Scorer.ChildScorer> getChildren()

Description copied from class: Scorer

Returns child sub-scorers positioned on the current document Note that this method should not be called on Scorers passed to LeafCollector.setScorer(Scorer), as these may be synthetic Scorers produced by BulkScorer which will throw an Exception.

Overrides:

getChildren in class Scorer