Package org.apache.lucene.search

Class ConstantScoreScorer

java.lang.Object

org.apache.lucene.search.Scorable

org.apache.lucene.search.Scorer

org.apache.lucene.search.ConstantScoreScorer

public final class ConstantScoreScorer
extends Scorer

A constant-scoring Scorer.

NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.

Nested Class Summary

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

Scorable.ChildScorable

Field Summary

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

weight

Constructor Summary

Constructors

Constructor	Description
ConstantScoreScorer(Weight weight, float score, ScoreMode scoreMode, DocIdSetIterator disi)	Constructor based on a DocIdSetIterator which will be used to drive iteration.
ConstantScoreScorer(Weight weight, float score, ScoreMode scoreMode, TwoPhaseIterator twoPhaseIterator)	Constructor based on a TwoPhaseIterator.

Method Summary

Modifier and Type	Method	Description
int	docID()	Returns the doc ID that is currently being scored.
float	getMaxScore(int upTo)	Return the maximum score that documents between the last target that this iterator was shallow-advanced to included and upTo included.
DocIdSetIterator	iterator()	Return a DocIdSetIterator over matching documents.
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.
TwoPhaseIterator	twoPhaseIterator()	Optional method: Return a TwoPhaseIterator view of this Scorer.

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

advanceShallow, getWeight

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

getChildren, smoothingScore

Methods inherited from class java.lang.Object

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

Constructor Detail

ConstantScoreScorer

public ConstantScoreScorer(Weight weight,
                           float score,
                           ScoreMode scoreMode,
                           DocIdSetIterator disi)

Constructor based on a DocIdSetIterator which will be used to drive iteration. Two phase iteration will not be supported.

Parameters:

weight - the parent weight

score - the score to return on each document

scoreMode - the score mode

disi - the iterator that defines matching documents

ConstantScoreScorer

public ConstantScoreScorer(Weight weight,
                           float score,
                           ScoreMode scoreMode,
                           TwoPhaseIterator twoPhaseIterator)

Constructor based on a TwoPhaseIterator. In that case the Scorer will support two-phase iteration.

Parameters:

weight - the parent weight

score - the score to return on each document

scoreMode - the score mode

twoPhaseIterator - the iterator that defines matching documents

Method Detail

getMaxScore

public float getMaxScore(int upTo)
                  throws IOException

Description copied from class: Scorer

Return the maximum score that documents between the last target that this iterator was shallow-advanced to included and upTo included.

Specified by:

getMaxScore in class Scorer

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

iterator

public DocIdSetIterator iterator()

Description copied from class: Scorer

Return a DocIdSetIterator over matching documents.

The returned iterator will either be positioned on -1 if no documents have been scored yet, DocIdSetIterator.NO_MORE_DOCS if all documents have been scored already, or the last document id that has been scored otherwise.

The returned iterator is a view: calling this method several times will return iterators that have the same state.

Specified by:

iterator in class Scorer

twoPhaseIterator

public TwoPhaseIterator twoPhaseIterator()

Description copied from class: Scorer

Optional method: Return a TwoPhaseIterator view of this Scorer. A return value of null indicates that two-phase iteration is not supported.

Note that the returned TwoPhaseIterator's approximation must advance synchronously with the Scorer.iterator(): advancing the approximation must advance the iterator and vice-versa.

Implementing this method is typically useful on Scorers that have a high per-document overhead in order to confirm matches.

The default implementation returns null.

Overrides:

twoPhaseIterator in class Scorer

docID

public int docID()

Description copied from class: Scorable

Returns the doc ID that is currently being scored.

Specified by:

docID in class Scorable

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