Package org.apache.lucene.queries.spans

Class SpanMultiTermQueryWrapper.FrequentTermsSpanBooleanQueryRewrite

java.lang.Object

org.apache.lucene.search.MultiTermQuery.RewriteMethod

org.apache.lucene.queries.spans.SpanMultiTermQueryWrapper.SpanRewriteMethod

org.apache.lucene.queries.spans.SpanMultiTermQueryWrapper.FrequentTermsSpanBooleanQueryRewrite

Enclosing class:

SpanMultiTermQueryWrapper<Q extends MultiTermQuery>

public static final class SpanMultiTermQueryWrapper.FrequentTermsSpanBooleanQueryRewrite
extends SpanMultiTermQueryWrapper.SpanRewriteMethod

A rewrite method that translates each term into a SpanTermQuery within a SpanOrQuery, but retains only the most frequent terms so it will not overflow the boolean max clause count.

Unlike SpanMultiTermQueryWrapper.TopTermsSpanBooleanQueryRewrite, which keeps the top terms by boost, this method ranks terms by their index statistics — document frequency, optionally breaking ties by total term frequency — and keeps the maxSize most frequent ones.

See Also:

• SpanMultiTermQueryWrapper.setRewriteMethod(org.apache.lucene.queries.spans.SpanMultiTermQueryWrapper.SpanRewriteMethod)

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final class	SpanMultiTermQueryWrapper.FrequentTermsSpanBooleanQueryRewrite.ScoreTerm	A collected term paired with its TermStates, used for ranking.

Field Summary

Fields

Modifier and Type	Field	Description
static final Comparator<SpanMultiTermQueryWrapper.FrequentTermsSpanBooleanQueryRewrite.ScoreTerm>	DF_ORDER	Ranks terms by document frequency; the least frequent term is dropped first.
static final Comparator<SpanMultiTermQueryWrapper.FrequentTermsSpanBooleanQueryRewrite.ScoreTerm>	DF_THEN_TTF_ORDER	Ranks terms by document frequency, breaking ties by total term frequency.

Constructor Summary

Constructors

Constructor	Description
FrequentTermsSpanBooleanQueryRewrite(int maxSize)	Create a rewrite that keeps at most maxSize terms, ranked by DF_ORDER.
FrequentTermsSpanBooleanQueryRewrite(int maxSize, Comparator<SpanMultiTermQueryWrapper.FrequentTermsSpanBooleanQueryRewrite.ScoreTerm> order)	Create a rewrite that keeps at most maxSize terms, ranked by order.

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object obj)
int	getMaxSize()	Returns the maximum number of terms retained by this rewrite.
int	hashCode()
SpanQuery	rewrite(IndexSearcher indexSearcher, MultiTermQuery query)

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

getTermsEnum

Methods inherited from class java.lang.Object

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

Field Details

DF_ORDER

public static final Comparator<SpanMultiTermQueryWrapper.FrequentTermsSpanBooleanQueryRewrite.ScoreTerm> DF_ORDER

Ranks terms by document frequency; the least frequent term is dropped first.

DF_THEN_TTF_ORDER

public static final Comparator<SpanMultiTermQueryWrapper.FrequentTermsSpanBooleanQueryRewrite.ScoreTerm> DF_THEN_TTF_ORDER

Ranks terms by document frequency, breaking ties by total term frequency.

Constructor Details

FrequentTermsSpanBooleanQueryRewrite

public FrequentTermsSpanBooleanQueryRewrite(int maxSize)

Create a rewrite that keeps at most maxSize terms, ranked by DF_ORDER.

FrequentTermsSpanBooleanQueryRewrite

public FrequentTermsSpanBooleanQueryRewrite(int maxSize,
 Comparator<SpanMultiTermQueryWrapper.FrequentTermsSpanBooleanQueryRewrite.ScoreTerm> order)

Create a rewrite that keeps at most maxSize terms, ranked by order.

Method Details

getMaxSize

public int getMaxSize()

Returns the maximum number of terms retained by this rewrite.

rewrite

public SpanQuery rewrite(IndexSearcher indexSearcher,
 MultiTermQuery query)
                  throws IOException

Specified by:

rewrite in class SpanMultiTermQueryWrapper.SpanRewriteMethod

Throws:

IOException

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object