Package org.apache.lucene.search
Class NGramPhraseQuery
- java.lang.Object
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- org.apache.lucene.search.Query
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- org.apache.lucene.search.NGramPhraseQuery
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public class NGramPhraseQuery extends Query
This is aPhraseQuery
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 thanPhraseQuery
, because NGramPhraseQuery willrewrite(IndexReader)
the query to "AB/0 CD/2", whilePhraseQuery
will query "AB/0 BC/1 CD/2" (where term/position).
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Constructor Summary
Constructors Constructor Description NGramPhraseQuery(int n, PhraseQuery query)
Constructor that takes gram size.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description boolean
equals(Object other)
Override and implement query instance equivalence properly in a subclass.int
getN()
Return the n in n-gramint[]
getPositions()
Return the list of relative positions that each term should appear at.Term[]
getTerms()
Return the list of terms.int
hashCode()
Override and implement query hash code properly in a subclass.Query
rewrite(IndexReader reader)
Expert: called to re-write queries into primitive queries.String
toString(String field)
Prints a query to a string, withfield
assumed to be the default field and omitted.void
visit(QueryVisitor visitor)
Recurse through the query tree, visiting any child queries-
Methods inherited from class org.apache.lucene.search.Query
classHash, createWeight, sameClassAs, toString
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Constructor Detail
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NGramPhraseQuery
public NGramPhraseQuery(int n, PhraseQuery query)
Constructor that takes gram size.- Parameters:
n
- n-gram size
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Method Detail
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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 classQuery
- Throws:
IOException
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visit
public void visit(QueryVisitor visitor)
Description copied from class:Query
Recurse through the query tree, visiting any child queries
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equals
public boolean equals(Object other)
Description copied from class:Query
Override and implement query instance equivalence properly in a subclass. This is required so thatQueryCache
works properly. Typically a query will be equal to another only if it's an instance of the same class and its document-filtering properties are identical that other instance. Utility methods are provided for certain repetitive code.- Specified by:
equals
in classQuery
- See Also:
Query.sameClassAs(Object)
,Query.classHash()
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hashCode
public int hashCode()
Description copied from class:Query
Override and implement query hash code properly in a subclass. This is required so thatQueryCache
works properly.- Specified by:
hashCode
in classQuery
- See Also:
Query.equals(Object)
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getN
public int getN()
Return the n in n-gram
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getTerms
public Term[] getTerms()
Return the list of terms.
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getPositions
public int[] getPositions()
Return the list of relative positions that each term should appear at.
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