org.apache.lucene.search

Class ScoringRewrite<B>

java.lang.Object

org.apache.lucene.search.MultiTermQuery.RewriteMethod

org.apache.lucene.search.TermCollectingRewrite<B>

org.apache.lucene.search.ScoringRewrite<B>

public abstract class ScoringRewrite<B>
extends TermCollectingRewrite<B>

Base rewrite method that translates each term into a query, and keeps the scores as computed by the query.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
(package private) class	ScoringRewrite.ParallelArraysTermCollector
(package private) static class	ScoringRewrite.TermFreqBoostByteStart Special implementation of BytesStartArray that keeps parallel arrays for boost and docFreq

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

TermCollectingRewrite.TermCollector

Field Summary

Fields

Modifier and Type	Field and Description
static MultiTermQuery.RewriteMethod	CONSTANT_SCORE_BOOLEAN_REWRITE Like SCORING_BOOLEAN_REWRITE except scores are not computed.
static ScoringRewrite<BooleanQuery.Builder>	SCORING_BOOLEAN_REWRITE A rewrite method that first translates each term into BooleanClause.Occur.SHOULD clause in a BooleanQuery, and keeps the scores as computed by the query.

Constructor Summary

Constructors

Constructor and Description
ScoringRewrite()

Method Summary

Modifier and Type	Method and Description
protected abstract void	checkMaxClauseCount(int count) This method is called after every new term to check if the number of max clauses (e.g.
Query	rewrite(IndexReader reader, MultiTermQuery query)

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

addClause, addClause, build, collectTerms, getTopLevelBuilder

Methods inherited from class org.apache.lucene.search.MultiTermQuery.RewriteMethod

getTermsEnum

Methods inherited from class java.lang.Object

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

Field Detail

SCORING_BOOLEAN_REWRITE

public static final ScoringRewrite<BooleanQuery.Builder> SCORING_BOOLEAN_REWRITE

A rewrite method that first translates each term into BooleanClause.Occur.SHOULD clause in a BooleanQuery, and keeps the scores as computed by the query. Note that typically such scores are meaningless to the user, and require non-trivial CPU to compute, so it's almost always better to use MultiTermQuery.CONSTANT_SCORE_REWRITE instead.

NOTE: This rewrite method will hit BooleanQuery.TooManyClauses if the number of terms exceeds BooleanQuery.getMaxClauseCount().

See Also:

MultiTermQuery.setRewriteMethod(org.apache.lucene.search.MultiTermQuery.RewriteMethod)

CONSTANT_SCORE_BOOLEAN_REWRITE

public static final MultiTermQuery.RewriteMethod CONSTANT_SCORE_BOOLEAN_REWRITE

Like SCORING_BOOLEAN_REWRITE except scores are not computed. Instead, each matching document receives a constant score equal to the query's boost.

NOTE: This rewrite method will hit BooleanQuery.TooManyClauses if the number of terms exceeds BooleanQuery.getMaxClauseCount().

See Also:

MultiTermQuery.setRewriteMethod(org.apache.lucene.search.MultiTermQuery.RewriteMethod)

Constructor Detail

ScoringRewrite

public ScoringRewrite()

Method Detail

checkMaxClauseCount

protected abstract void checkMaxClauseCount(int count)
                                     throws java.io.IOException

This method is called after every new term to check if the number of max clauses (e.g. in BooleanQuery) is not exceeded. Throws the corresponding RuntimeException.

Throws:

java.io.IOException

rewrite

public final Query rewrite(IndexReader reader,
                           MultiTermQuery query)
                    throws java.io.IOException

Specified by:

rewrite in class MultiTermQuery.RewriteMethod

Throws:

java.io.IOException