org.apache.lucene.search
Class NGramPhraseQuery

java.lang.Object
  org.apache.lucene.search.Query
      org.apache.lucene.search.PhraseQuery
          org.apache.lucene.search.NGramPhraseQuery

All Implemented Interfaces:

Cloneable

public class NGramPhraseQuery
extends PhraseQuery

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

NGramPhraseQuery(int n)
Constructor that takes gram size.

Method Summary

boolean	equals(Object o) Returns true iff o is equal to this.
int	hashCode() Returns a hash code value for this object.
Query	rewrite(IndexReader reader) Expert: called to re-write queries into primitive queries.

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

add, add, createWeight, extractTerms, getPositions, getSlop, getTerms, setSlop, toString

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

clone, getBoost, setBoost, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

NGramPhraseQuery

public NGramPhraseQuery(int n)

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 PhraseQuery

Throws:

IOException

equals

public boolean equals(Object o)

Returns true iff o is equal to this.

Overrides:

equals in class PhraseQuery

hashCode

public int hashCode()

Returns a hash code value for this object.

Overrides:

hashCode in class PhraseQuery