org.apache.lucene.search

Class ConstantScoreWeight

java.lang.Object

org.apache.lucene.search.Weight

org.apache.lucene.search.ConstantScoreWeight

Direct Known Subclasses:

RandomAccessWeight

public abstract class ConstantScoreWeight
extends Weight

A Weight that has a constant score equal to the boost of the wrapped query. This is typically useful when building queries which do not produce meaningful scores and are mostly useful for filtering.

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.Weight

Weight.DefaultBulkScorer

Field Summary

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

parentQuery

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	ConstantScoreWeight(Query query)

Method Summary

Methods

Modifier and Type	Method and Description
Explanation	explain(LeafReaderContext context, int doc) An explanation of the score computation for the named document.
void	extractTerms(Set<Term> terms) Expert: adds all terms occurring in this query to the terms set.
float	getValueForNormalization() The value for normalization of contained query clauses (e.g.
void	normalize(float norm, float topLevelBoost) Assigns the query normalization factor and boost from parent queries to this.
protected float	score() Return the score produced by this Weight.

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

bulkScorer, getQuery, scorer

Methods inherited from class java.lang.Object

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

Constructor Detail

ConstantScoreWeight

protected ConstantScoreWeight(Query query)

Method Detail

extractTerms

public void extractTerms(Set<Term> terms)

Description copied from class: Weight

Expert: adds all terms occurring in this query to the terms set. If the Weight was created with needsScores == true then this method will only extract terms which are used for scoring, otherwise it will extract all terms which are used for matching.

Specified by:

extractTerms in class Weight

getValueForNormalization

public final float getValueForNormalization()
                                     throws IOException

Description copied from class: Weight

The value for normalization of contained query clauses (e.g. sum of squared weights).

Specified by:

getValueForNormalization in class Weight

Throws:

IOException

normalize

public final void normalize(float norm,
             float topLevelBoost)

Description copied from class: Weight

Assigns the query normalization factor and boost from parent queries to this.

Specified by:

normalize in class Weight

score

protected final float score()

Return the score produced by this Weight.

explain

public final Explanation explain(LeafReaderContext context,
                  int doc)
                          throws IOException

Description copied from class: Weight

An explanation of the score computation for the named document.

Specified by:

explain in class Weight

Parameters:

context - the readers context to create the Explanation for.

doc - the document's id relative to the given context's reader

Returns:

an Explanation for the score

Throws:

IOException - if an IOException occurs