Package org.apache.lucene.search

Class ScorerSupplier

java.lang.Object

org.apache.lucene.search.ScorerSupplier

public abstract class ScorerSupplier
extends Object

A supplier of Scorer. This allows to get an estimate of the cost before building the Scorer.

Constructor Summary

Constructors

Constructor	Description
ScorerSupplier()

Method Summary

Modifier and Type	Method	Description
abstract long	cost()	Get an estimate of the Scorer that would be returned by get(long).
abstract Scorer	get(long leadCost)	Get the Scorer.
void	setTopLevelScoringClause()	Inform this ScorerSupplier that its returned scorers produce scores that get passed to the collector, as opposed to partial scores that then need to get combined (e.g.

Methods inherited from class java.lang.Object

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

Constructor Detail

ScorerSupplier

public ScorerSupplier()

Method Detail

get

public abstract Scorer get(long leadCost)
                    throws IOException

Get the Scorer. This may not return null and must be called at most once.

Parameters:

leadCost - Cost of the scorer that will be used in order to lead iteration. This can be interpreted as an upper bound of the number of times that DocIdSetIterator.nextDoc(), DocIdSetIterator.advance(int) and TwoPhaseIterator.matches() will be called. Under doubt, pass Long.MAX_VALUE, which will produce a Scorer that has good iteration capabilities.

Throws:

IOException

cost

public abstract long cost()

Get an estimate of the Scorer that would be returned by get(long). This may be a costly operation, so it should only be called if necessary.

See Also:

DocIdSetIterator.cost()

setTopLevelScoringClause

public void setTopLevelScoringClause()
                              throws IOException

Inform this ScorerSupplier that its returned scorers produce scores that get passed to the collector, as opposed to partial scores that then need to get combined (e.g. summed up). Note that this method also gets called if scores are not requested, e.g. because the score mode is ScoreMode.COMPLETE_NO_SCORES, so implementations should look at both the score mode and this boolean to know whether to prepare for reacting to Scorable.setMinCompetitiveScore(float) calls.

Throws:

IOException