org.apache.lucene.search

Class ScoringRewrite<B>

java.lang.Object

org.apache.lucene.search.MultiTermQuery.RewriteMethod

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

public abstract class ScoringRewrite<B>
extends MultiTermQuery.RewriteMethod

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

NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.

Only public to be accessible by spans package.

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 void	addClause(B topLevel, Term term, int docCount, float boost) Add a MultiTermQuery term to the top-level query builder.
protected abstract void	addClause(B topLevel, Term term, int docCount, float boost, TermStates states)
protected abstract Query	build(B builder) Finalize the creation of the query from the builder.
protected abstract void	checkMaxClauseCount(int count) This method is called after every new term to check if the number of max clauses (e.g.
protected abstract B	getTopLevelBuilder() Return a suitable builder for the top-level Query for holding all expanded terms.
Query	rewrite(IndexReader reader, MultiTermQuery query)

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 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:

IOException

rewrite

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

Specified by:

rewrite in class MultiTermQuery.RewriteMethod

Throws:

IOException

getTopLevelBuilder

protected abstract B getTopLevelBuilder()
                                 throws IOException

Return a suitable builder for the top-level Query for holding all expanded terms.

Throws:

IOException

build

protected abstract Query build(B builder)

Finalize the creation of the query from the builder.

addClause

protected final void addClause(B topLevel,
                               Term term,
                               int docCount,
                               float boost)
                        throws IOException

Add a MultiTermQuery term to the top-level query builder.

Throws:

IOException

addClause

protected abstract void addClause(B topLevel,
                                  Term term,
                                  int docCount,
                                  float boost,
                                  TermStates states)
                           throws IOException

Throws:

IOException