org.apache.lucene.search

Class ConstantScoreQuery

java.lang.Object

org.apache.lucene.search.Query

org.apache.lucene.search.ConstantScoreQuery

public final class ConstantScoreQuery
extends Query

A query that wraps another query and simply returns a constant score equal to 1 for every document that matches the query. It therefore simply strips of all scores and always returns 1.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected class	ConstantScoreQuery.ConstantBulkScorer We return this as our BulkScorer so that if the CSQ wraps a query with its own optimized top-level scorer (e.g.

Field Summary

Fields

Modifier and Type	Field and Description
private Query	query

Constructor Summary

Constructors

Constructor and Description
ConstantScoreQuery(Query query) Strips off scores from the passed in Query.

Method Summary

Modifier and Type	Method and Description
Weight	createWeight(IndexSearcher searcher, boolean needsScores) Expert: Constructs an appropriate Weight implementation for this query.
boolean	equals(java.lang.Object other) Override and implement query instance equivalence properly in a subclass.
Query	getQuery() Returns the encapsulated query.
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.
java.lang.String	toString(java.lang.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

classHash, sameClassAs, toString

Methods inherited from class java.lang.Object

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

Field Detail

query

private final Query query

Constructor Detail

ConstantScoreQuery

public ConstantScoreQuery(Query query)

Strips off scores from the passed in Query. The hits will get a constant score of 1.

Method Detail

getQuery

public Query getQuery()

Returns the encapsulated query.

rewrite

public Query rewrite(IndexReader reader)
              throws java.io.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:

java.io.IOException

createWeight

public Weight createWeight(IndexSearcher searcher,
                           boolean needsScores)
                    throws java.io.IOException

Description copied from class: Query

Expert: Constructs an appropriate Weight implementation for this query.

Only implemented by primitive queries, which re-write to themselves.

Overrides:

createWeight in class Query

needsScores - True if document scores (Scorer.score()) or match frequencies (Scorer.freq()) are needed.

Throws:

java.io.IOException

toString

public java.lang.String toString(java.lang.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

equals

public boolean equals(java.lang.Object other)

Description copied from class: Query

Override and implement query instance equivalence properly in a subclass. This is required so that QueryCache 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 class Query

See Also:

Query.sameClassAs(Object), Query.classHash()

hashCode

public int hashCode()

Description copied from class: Query

Override and implement query hash code properly in a subclass. This is required so that QueryCache works properly.

Specified by:

hashCode in class Query

See Also:

Query.equals(Object)