Package org.apache.lucene.queries.function

Class ValueSourceScorer

java.lang.Object

org.apache.lucene.search.Scorable

org.apache.lucene.search.Scorer

org.apache.lucene.queries.function.ValueSourceScorer

public abstract class ValueSourceScorer
extends Scorer

Scorer which returns the result of FunctionValues.floatVal(int) as the score for a document, and which filters out documents that don't match matches(int). This Scorer has a TwoPhaseIterator. This is similar to FunctionQuery, with an added filter.

Note: If the scores are needed, then the underlying value will probably be fetched/computed twice -- once to filter and next to return the score. If that's non-trivial then consider wrapping it in an implementation that will cache the current value.

See Also:

FunctionQuery

WARNING: This API is experimental 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

Modifier and Type	Field	Description
protected FunctionValues	values

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

weight

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	ValueSourceScorer(Weight weight, LeafReaderContext readerContext, FunctionValues values)

Method Summary

Modifier and Type	Method	Description
int	docID()
float	getMaxScore(int upTo)
DocIdSetIterator	iterator()
protected float	matchCost()	Cost evaluation function which defines the cost of access for the TwoPhaseIterator for this class This method should be overridden for specifying custom cost methods.
abstract boolean	matches(int doc)	Override to decide if this document matches.
float	score()
TwoPhaseIterator	twoPhaseIterator()

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

advanceShallow, getWeight

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

getChildren, setMinCompetitiveScore, smoothingScore

Methods inherited from class java.lang.Object

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

Field Detail

values

protected final FunctionValues values

Constructor Detail

ValueSourceScorer

protected ValueSourceScorer(Weight weight,
                            LeafReaderContext readerContext,
                            FunctionValues values)

Method Detail

matches

public abstract boolean matches(int doc)
                         throws IOException

Override to decide if this document matches. It's called by TwoPhaseIterator.matches().

Throws:

IOException

iterator

public DocIdSetIterator iterator()

Specified by:

iterator in class Scorer

twoPhaseIterator

public TwoPhaseIterator twoPhaseIterator()

Overrides:

twoPhaseIterator in class Scorer

docID

public int docID()

Specified by:

docID in class Scorable

score

public float score()
            throws IOException

Specified by:

score in class Scorable

Throws:

IOException

getMaxScore

public float getMaxScore(int upTo)
                  throws IOException

Specified by:

getMaxScore in class Scorer

Throws:

IOException

matchCost

protected float matchCost()

Cost evaluation function which defines the cost of access for the TwoPhaseIterator for this class This method should be overridden for specifying custom cost methods. Used by TwoPhaseIterator.matchCost() for the instance owned by this class

Returns:

cost of access

WARNING: This API is experimental and might change in incompatible ways in the next release.