Package org.apache.lucene.search

Class ScoreCachingWrappingScorer

java.lang.Object

org.apache.lucene.search.Scorable

org.apache.lucene.search.ScoreCachingWrappingScorer

public final class ScoreCachingWrappingScorer
extends Scorable

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.Scorable

Scorable.ChildScorable

Method Summary

Modifier and Type	Method	Description
int	docID()	Returns the doc ID that is currently being scored.
Collection<Scorable.ChildScorable>	getChildren()	Returns child sub-scorers positioned on the current document
float	score()	Returns the score of the current document matching the query.
void	setMinCompetitiveScore(float minScore)	Optional method: Tell the scorer that its iterator may safely ignore all documents whose score is less than the given minScore.
static Scorable	wrap(Scorable scorer)	Wraps the provided Scorable unless it's already an instance of ScoreCachingWrappingScorer, in which case it will just return the provided instance.

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

smoothingScore

Methods inherited from class java.lang.Object

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

Method Detail

wrap

public static Scorable wrap(Scorable scorer)

Wraps the provided Scorable unless it's already an instance of ScoreCachingWrappingScorer, in which case it will just return the provided instance.

Parameters:

scorer - Underlying Scorable to wrap

Returns:

Instance of ScoreCachingWrappingScorer wrapping the underlying scorer

score

public float score()
            throws IOException

Description copied from class: Scorable

Returns the score of the current document matching the query.

Specified by:

score in class Scorable

Throws:

IOException

setMinCompetitiveScore

public void setMinCompetitiveScore(float minScore)
                            throws IOException

Description copied from class: Scorable

Optional method: Tell the scorer that its iterator may safely ignore all documents whose score is less than the given minScore. This is a no-op by default.

This method may only be called from collectors that use ScoreMode.TOP_SCORES, and successive calls may only set increasing values of minScore.

Overrides:

setMinCompetitiveScore in class Scorable

Throws:

IOException

docID

public int docID()

Description copied from class: Scorable

Returns the doc ID that is currently being scored.

Specified by:

docID in class Scorable

getChildren

public Collection<Scorable.ChildScorable> getChildren()

Description copied from class: Scorable

Returns child sub-scorers positioned on the current document

Overrides:

getChildren in class Scorable