Package org.apache.lucene.queries

Class CustomScoreQuery

java.lang.Object

org.apache.lucene.search.Query

org.apache.lucene.queries.CustomScoreQuery

All Implemented Interfaces:

java.lang.Cloneable

public class CustomScoreQuery
extends Query

Query that sets document score as a programmatic function of several (sub) scores:

1. the score of its subQuery (any query)
2. (optional) the score of its FunctionQuery (or queries).

Subclasses can modify the computation by overriding getCustomScoreProvider(org.apache.lucene.index.AtomicReaderContext).

Constructor Summary

Constructors

Constructor	Description
CustomScoreQuery(Query subQuery)	Create a CustomScoreQuery over input subQuery.
CustomScoreQuery(Query subQuery, FunctionQuery scoringQuery)	Create a CustomScoreQuery over input subQuery and a FunctionQuery.
CustomScoreQuery(Query subQuery, FunctionQuery... scoringQueries)	Create a CustomScoreQuery over input subQuery and a FunctionQuery.

Method Summary

Modifier and Type	Method	Description
CustomScoreQuery	clone()	Returns a clone of this query.
Weight	createWeight(IndexSearcher searcher)	Expert: Constructs an appropriate Weight implementation for this query.
boolean	equals(java.lang.Object o)	Returns true if o is equal to this.
void	extractTerms(java.util.Set<Term> terms)	Expert: adds all terms occurring in this query to the terms set.
Query[]	getScoringQueries()	The scoring queries that only affect the score of CustomScoreQuery.
Query	getSubQuery()	The sub-query that CustomScoreQuery wraps, affecting both the score and which documents match.
int	hashCode()	Returns a hash code value for this object.
boolean	isStrict()	Checks if this is strict custom scoring.
java.lang.String	name()	A short name of this query, used in toString(String).
Query	rewrite(IndexReader reader)	Expert: called to re-write queries into primitive queries.
void	setStrict(boolean strict)	Set the strict mode of this query.
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

getBoost, setBoost, toString

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

CustomScoreQuery

public CustomScoreQuery(Query subQuery)

Create a CustomScoreQuery over input subQuery.

Parameters:

subQuery - the sub query whose scored is being customized. Must not be null.

CustomScoreQuery

public CustomScoreQuery(Query subQuery,
                        FunctionQuery scoringQuery)

Create a CustomScoreQuery over input subQuery and a FunctionQuery.

Parameters:

subQuery - the sub query whose score is being customized. Must not be null.

scoringQuery - a value source query whose scores are used in the custom score computation. This parameter is optional - it can be null.

CustomScoreQuery

public CustomScoreQuery(Query subQuery,
                        FunctionQuery... scoringQueries)

Create a CustomScoreQuery over input subQuery and a FunctionQuery.

Parameters:

subQuery - the sub query whose score is being customized. Must not be null.

scoringQueries - value source queries whose scores are used in the custom score computation. This parameter is optional - it can be null or even an empty array.

Method Detail

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

extractTerms

public void extractTerms(java.util.Set<Term> terms)

Description copied from class: Query

Expert: adds all terms occurring in this query to the terms set. Only works if this query is in its rewritten form.

Overrides:

extractTerms in class Query

clone

public CustomScoreQuery clone()

Description copied from class: Query

Returns a clone of this query.

Overrides:

clone in class Query

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 o)

Returns true if o is equal to this.

Overrides:

equals in class Query

hashCode

public int hashCode()

Returns a hash code value for this object.

Overrides:

hashCode in class Query

createWeight

public Weight createWeight(IndexSearcher searcher)
                    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

Throws:

java.io.IOException

isStrict

public boolean isStrict()

Checks if this is strict custom scoring. In strict custom scoring, the ValueSource part does not participate in weight normalization. This may be useful when one wants full control over how scores are modified, and does not care about normalizing by the ValueSource part. One particular case where this is useful if for testing this query.

Note: only has effect when the ValueSource part is not null.

setStrict

public void setStrict(boolean strict)

Set the strict mode of this query.

Parameters:

strict - The strict mode to set.

See Also:

isStrict()

getSubQuery

public Query getSubQuery()

The sub-query that CustomScoreQuery wraps, affecting both the score and which documents match.

getScoringQueries

public Query[] getScoringQueries()

The scoring queries that only affect the score of CustomScoreQuery.

name

public java.lang.String name()

A short name of this query, used in toString(String).