org.apache.lucene.search

Class ReqExclScorer

java.lang.Object

org.apache.lucene.search.Scorer

org.apache.lucene.search.ReqExclScorer

class ReqExclScorer
extends Scorer

A Scorer for queries with a required subscorer and an excluding (prohibited) sub Scorer.

Nested Class Summary

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

Scorer.ChildScorer

Field Summary

Fields

Modifier and Type	Field and Description
private static int	ADVANCE_COST Estimation of the number of operations required to call DISI.advance.
private DocIdSetIterator	exclApproximation
private TwoPhaseIterator	exclTwoPhaseIterator
private DocIdSetIterator	reqApproximation
private Scorer	reqScorer
private TwoPhaseIterator	reqTwoPhaseIterator

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

weight

Constructor Summary

Constructors

Constructor and Description
ReqExclScorer(Scorer reqScorer, Scorer exclScorer) Construct a ReqExclScorer.

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
java.util.Collection<Scorer.ChildScorer>	getChildren() Returns child sub-scorers
DocIdSetIterator	iterator() Return a DocIdSetIterator over matching documents.
private static float	matchCost(DocIdSetIterator reqApproximation, TwoPhaseIterator reqTwoPhaseIterator, DocIdSetIterator exclApproximation, TwoPhaseIterator exclTwoPhaseIterator)
private static boolean	matchesOrNull(TwoPhaseIterator it) Confirms whether or not the given TwoPhaseIterator matches on the current document.
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

getWeight

Methods inherited from class java.lang.Object

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

Field Detail

reqScorer

private final Scorer reqScorer

reqApproximation

private final DocIdSetIterator reqApproximation

exclApproximation

private final DocIdSetIterator exclApproximation

reqTwoPhaseIterator

private final TwoPhaseIterator reqTwoPhaseIterator

exclTwoPhaseIterator

private final TwoPhaseIterator exclTwoPhaseIterator

ADVANCE_COST

private static final int ADVANCE_COST

Estimation of the number of operations required to call DISI.advance. This is likely completely wrong, especially given that the cost of this method usually depends on how far you want to advance, but it's probably better than nothing.

See Also:

Constant Field Values

Constructor Detail

ReqExclScorer

public ReqExclScorer(Scorer reqScorer,
                     Scorer exclScorer)

Construct a ReqExclScorer.

Parameters:

reqScorer - The scorer that must match, except where

exclScorer - indicates exclusion.

Method Detail

matchesOrNull

private static boolean matchesOrNull(TwoPhaseIterator it)
                              throws java.io.IOException

Confirms whether or not the given TwoPhaseIterator matches on the current document.

Throws:

java.io.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

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()

freq

public int freq()
         throws java.io.IOException

Description copied from class: Scorer

Returns the freq of this Scorer on the current document

Specified by:

freq in class Scorer

Throws:

java.io.IOException

score

public float score()
            throws java.io.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:

java.io.IOException

getChildren

public java.util.Collection<Scorer.ChildScorer> getChildren()

Description copied from class: Scorer

Returns child sub-scorers

Overrides:

getChildren in class Scorer

matchCost

private static float matchCost(DocIdSetIterator reqApproximation,
                               TwoPhaseIterator reqTwoPhaseIterator,
                               DocIdSetIterator exclApproximation,
                               TwoPhaseIterator exclTwoPhaseIterator)

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