Package org.apache.lucene.search

Class BooleanQuery.BooleanWeight

java.lang.Object

org.apache.lucene.search.Weight

org.apache.lucene.search.BooleanQuery.BooleanWeight

Enclosing class:

BooleanQuery

protected class BooleanQuery.BooleanWeight
extends Weight

Expert: the Weight for BooleanQuery, used to normalize, score and explain these queries.

NOTE: this API and implementation is subject to change suddenly in the next release.

Field Summary

Fields

Modifier and Type	Field	Description
protected int	maxCoord
protected Similarity	similarity	The Similarity implementation.
protected ArrayList<Weight>	weights

Constructor Summary

Constructors

Constructor	Description
BooleanWeight(IndexSearcher searcher, boolean disableCoord)

Method Summary

Modifier and Type	Method	Description
float	coord(int overlap, int maxOverlap)
Explanation	explain(AtomicReaderContext context, int doc)	An explanation of the score computation for the named document.
Query	getQuery()	The query that this concerns.
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.
Scorer	scorer(AtomicReaderContext context, boolean scoreDocsInOrder, boolean topScorer, Bits acceptDocs)	Returns a Scorer which scores documents in/out-of order according to scoreDocsInOrder.
boolean	scoresDocsOutOfOrder()	Returns true iff this implementation scores docs only out of order.

Methods inherited from class java.lang.Object

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

Field Detail

similarity

protected Similarity similarity

The Similarity implementation.

weights

protected ArrayList<Weight> weights

maxCoord

protected int maxCoord

Constructor Detail

BooleanWeight

public BooleanWeight(IndexSearcher searcher,
                     boolean disableCoord)
              throws IOException

Throws:

IOException

Method Detail

getQuery

public Query getQuery()

Description copied from class: Weight

The query that this concerns.

Specified by:

getQuery in class Weight

getValueForNormalization

public 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

coord

public float coord(int overlap,
                   int maxOverlap)

normalize

public 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

explain

public Explanation explain(AtomicReaderContext 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

scorer

public Scorer scorer(AtomicReaderContext context,
                     boolean scoreDocsInOrder,
                     boolean topScorer,
                     Bits acceptDocs)
              throws IOException

Description copied from class: Weight

Returns a Scorer which scores documents in/out-of order according to scoreDocsInOrder.

NOTE: even if scoreDocsInOrder is false, it is recommended to check whether the returned Scorer indeed scores documents out of order (i.e., call Weight.scoresDocsOutOfOrder()), as some Scorer implementations will always return documents in-order.
NOTE: null can be returned if no documents will be scored by this query.

Specified by:

scorer in class Weight

Parameters:

context - the AtomicReaderContext for which to return the Scorer.

scoreDocsInOrder - specifies whether in-order scoring of documents is required. Note that if set to false (i.e., out-of-order scoring is required), this method can return whatever scoring mode it supports, as every in-order scorer is also an out-of-order one. However, an out-of-order scorer may not support DocIdSetIterator.nextDoc() and/or DocIdSetIterator.advance(int), therefore it is recommended to request an in-order scorer if use of these methods is required.

topScorer - if true, Scorer.score(Collector) will be called; if false, DocIdSetIterator.nextDoc() and/or DocIdSetIterator.advance(int) will be called.

acceptDocs - Bits that represent the allowable docs to match (typically deleted docs but possibly filtering other documents)

Returns:

a Scorer which scores documents in/out-of order.

Throws:

IOException - if there is a low-level I/O error

scoresDocsOutOfOrder

public boolean scoresDocsOutOfOrder()

Description copied from class: Weight

Returns true iff this implementation scores docs only out of order. This method is used in conjunction with Collector's acceptsDocsOutOfOrder and Weight.scorer(AtomicReaderContext, boolean, boolean, Bits) to create a matching Scorer instance for a given Collector, or vice versa.

NOTE: the default implementation returns false, i.e. the Scorer scores documents in-order.

Overrides:

scoresDocsOutOfOrder in class Weight