Module org.apache.lucene.core

Package org.apache.lucene.search

Class ReqExclScorer

java.lang.Object

org.apache.lucene.search.Scorable

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.Scorable

Scorable.ChildScorable

Field Summary

Fields

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

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

weight

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method	Description
int	advanceShallow(int target)	Advance to the block of documents that contains target in order to get scoring information about this block.
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	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.
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.
void	setMinCompetitiveScore(float score)	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

getWeight

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

Field Details

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 Details

ReqExclScorer

public ReqExclScorer(Scorer reqScorer,
 Scorer exclScorer)

Construct a ReqExclScorer.

Parameters:

reqScorer - The scorer that must match, except where

exclScorer - indicates exclusion.

Method Details

matchesOrNull

private static boolean matchesOrNull(TwoPhaseIterator it)
                              throws IOException

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

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

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

advanceShallow

public int advanceShallow(int target)
                   throws IOException

Description copied from class: Scorer

Advance to the block of documents that contains target in order to get scoring information about this block. This method is implicitly called by DocIdSetIterator.advance(int) and DocIdSetIterator.nextDoc() on the returned doc ID. Calling this method doesn't modify the current DocIdSetIterator.docID(). It returns a number that is greater than or equal to all documents contained in the current block, but less than any doc IDS of the next block. target must be >= Scorable.docID() as well as all targets that have been passed to Scorer.advanceShallow(int) so far.

Overrides:

advanceShallow in class Scorer

Throws:

IOException

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 score)
                            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

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

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