org.apache.lucene.search

Class ConstantScoreScorer

java.lang.Object

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.Scorer

Scorer.ChildScorer

Field Summary

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

weight

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method and Description
int	docID() Returns the doc ID that is currently being scored.
int	freq() Returns the freq of this Scorer on the current document
DocIdSetIterator	iterator() Return a DocIdSetIterator over matching documents.
float	score() Returns the score of the current document matching the query.
TwoPhaseIterator	twoPhaseIterator() Optional method: Return a TwoPhaseIterator view of this Scorer.

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

getChildren, getWeight

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,
                           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

disi - the iterator that defines matching documents

ConstantScoreScorer

public ConstantScoreScorer(Weight weight,
                           float score,
                           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

twoPhaseIterator - the iterator that defines matching documents

Method Detail

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: Scorer

Returns the doc ID that is currently being scored. This will return -1 if the Scorer.iterator() is not positioned or DocIdSetIterator.NO_MORE_DOCS if it has been entirely consumed.

Specified by:

docID in class Scorer

See Also:

DocIdSetIterator.docID()

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).

Specified by:

score in class Scorer

Throws:

IOException

freq

public int freq()
         throws IOException

Description copied from class: Scorer

Returns the freq of this Scorer on the current document

Specified by:

freq in class Scorer

Throws:

IOException