org.apache.lucene.search

Class ConstantScoreQuery.ConstantScorer

java.lang.Object

org.apache.lucene.search.DocIdSetIterator

org.apache.lucene.search.Scorer

org.apache.lucene.search.ConstantScoreQuery.ConstantScorer

Enclosing class:

ConstantScoreQuery

protected class ConstantScoreQuery.ConstantScorer
extends Scorer

Nested Class Summary

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

Scorer.ScorerVisitor<P extends Query,C extends Query,S extends Scorer>

Field Summary

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

weight

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

NO_MORE_DOCS

Constructor Summary

Constructors

Constructor and Description
ConstantScorer(Similarity similarity, DocIdSetIterator docIdSetIterator, Weight w)

Method Summary

Modifier and Type	Method and Description
int	advance(int target) Advances to the first beyond (see NOTE below) the current whose document number is greater than or equal to target.
int	docID() Returns the following: -1 or DocIdSetIterator.NO_MORE_DOCS if DocIdSetIterator.nextDoc() or DocIdSetIterator.advance(int) were not called yet.
int	nextDoc() Advances to the next document in the set and returns the doc it is currently on, or DocIdSetIterator.NO_MORE_DOCS if there are no more docs in the set. NOTE: after the iterator has exhausted you should not call this method, as it may result in unpredicted behavior.
float	score() Returns the score of the current document matching the query.
void	score(Collector collector) Scores and collects all matching documents.
protected boolean	score(Collector collector, int max, int firstDocID) Expert: Collects matching documents in a range.

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

freq, getSimilarity, visitScorers, visitSubScorers

Methods inherited from class java.lang.Object

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

Constructor Detail

ConstantScorer

public ConstantScorer(Similarity similarity,
                      DocIdSetIterator docIdSetIterator,
                      Weight w)
               throws java.io.IOException

Throws:

java.io.IOException

Method Detail

nextDoc

public int nextDoc()
            throws java.io.IOException

Description copied from class: DocIdSetIterator

Advances to the next document in the set and returns the doc it is currently on, or DocIdSetIterator.NO_MORE_DOCS if there are no more docs in the set.
NOTE: after the iterator has exhausted you should not call this method, as it may result in unpredicted behavior.

Specified by:

nextDoc in class DocIdSetIterator

Throws:

java.io.IOException

docID

public int docID()

Description copied from class: DocIdSetIterator

Returns the following:

• -1 or DocIdSetIterator.NO_MORE_DOCS if DocIdSetIterator.nextDoc() or DocIdSetIterator.advance(int) were not called yet.
• DocIdSetIterator.NO_MORE_DOCS if the iterator has exhausted.
• Otherwise it should return the doc ID it is currently on.

Specified by:

docID in class DocIdSetIterator

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 the first time, or when called from within Collector.collect(int).

Specified by:

score in class Scorer

Throws:

java.io.IOException

advance

public int advance(int target)
            throws java.io.IOException

Description copied from class: DocIdSetIterator

Advances to the first beyond (see NOTE below) the current whose document number is greater than or equal to target. Returns the current document number or DocIdSetIterator.NO_MORE_DOCS if there are no more docs in the set.

Behaves as if written:

 int advance(int target) {
   int doc;
   while ((doc = nextDoc()) < target) {
   }
   return doc;
 }
 

Some implementations are considerably more efficient than that.

NOTE: when target ≤ current implementations may opt not to advance beyond their current DocIdSetIterator.docID().

NOTE: this method may be called with DocIdSetIterator.NO_MORE_DOCS for efficiency by some Scorers. If your implementation cannot efficiently determine that it should exhaust, it is recommended that you check for that value in each call to this method.

NOTE: after the iterator has exhausted you should not call this method, as it may result in unpredicted behavior.

Specified by:

advance in class DocIdSetIterator

Throws:

java.io.IOException

score

public void score(Collector collector)
           throws java.io.IOException

Description copied from class: Scorer

Scores and collects all matching documents.

Overrides:

score in class Scorer

Parameters:

collector - The collector to which all matching documents are passed.

Throws:

java.io.IOException

score

protected boolean score(Collector collector,
                        int max,
                        int firstDocID)
                 throws java.io.IOException

Description copied from class: Scorer

Expert: Collects matching documents in a range. Hook for optimization. Note, firstDocID is added to ensure that DocIdSetIterator.nextDoc() was called before this method.

NOTE: Because of backwards compatibility, this method is still declared as protected, but it is intended to be public, because it's called from other classes (like BooleanScorer). If you subclass Scorer, you should declare the overridden method as public to ease transition to Lucene 4.0, where it will be public.

Overrides:

score in class Scorer

Parameters:

collector - The collector to which all matching documents are passed.

max - Do not score documents past this.

firstDocID - The first document ID (ensures DocIdSetIterator.nextDoc() is called before this method.

Returns:

true if more matching documents may remain.

Throws:

java.io.IOException