org.apache.lucene.search

Class NGramPhraseQuery

java.lang.Object

org.apache.lucene.search.Query

org.apache.lucene.search.NGramPhraseQuery

All Implemented Interfaces:

Cloneable

public class NGramPhraseQuery
extends Query

This is a PhraseQuery which is optimized for n-gram phrase query. For example, when you query "ABCD" on a 2-gram field, you may want to use NGramPhraseQuery rather than PhraseQuery, because NGramPhraseQuery will rewrite(IndexReader) the query to "AB/0 CD/2", while PhraseQuery will query "AB/0 BC/1 CD/2" (where term/position).

Constructor Summary

Constructors

Constructor and Description
NGramPhraseQuery(int n, PhraseQuery query) Constructor that takes gram size.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	equals(Object o)
float	getBoost() Gets the boost for this clause.
int[]	getPositions() Return the list of relative positions that each term should appear at.
Term[]	getTerms() Return the list of terms.
int	hashCode()
Query	rewrite(IndexReader reader) Expert: called to re-write queries into primitive queries.
void	setBoost(float b) Sets the boost for this query clause to b.
String	toString(String field) Prints a query to a string, with field assumed to be the default field and omitted.

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

clone, createWeight, toString

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

NGramPhraseQuery

public NGramPhraseQuery(int n,
                PhraseQuery query)

Constructor that takes gram size.

Parameters:

n - n-gram size

Method Detail

rewrite

public Query rewrite(IndexReader reader)
              throws IOException

Description copied from class: Query

Expert: called to re-write queries into primitive queries. For example, a PrefixQuery will be rewritten into a BooleanQuery that consists of TermQuerys.

Overrides:

rewrite in class Query

Throws:

IOException

equals

public boolean equals(Object o)

Overrides:

equals in class Query

hashCode

public int hashCode()

Overrides:

hashCode in class Query

getTerms

public Term[] getTerms()

Return the list of terms.

getPositions

public int[] getPositions()

Return the list of relative positions that each term should appear at.

getBoost

public float getBoost()

Description copied from class: Query

Gets the boost for this clause. Documents matching this clause will (in addition to the normal weightings) have their score multiplied by b. The boost is 1.0 by default.

Overrides:

getBoost in class Query

setBoost

public void setBoost(float b)

Description copied from class: Query

Sets the boost for this query clause to b. Documents matching this clause will (in addition to the normal weightings) have their score multiplied by b.

Overrides:

setBoost in class Query

toString

public String toString(String field)

Description copied from class: Query

Prints a query to a string, with field assumed to be the default field and omitted.

Specified by:

toString in class Query