Module org.apache.lucene.queries

Package org.apache.lucene.queries.function

Class FunctionQuery

java.lang.Object

org.apache.lucene.search.Query

org.apache.lucene.queries.function.FunctionQuery

public class FunctionQuery
extends Query

Returns a score for each document based on a ValueSource, often some function of the value of a field.

See Also:

• ValueSourceScorer

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected class	FunctionQuery.AllScorer	Scores all documents, applying the function to each document
protected class	FunctionQuery.FunctionWeight	Creates FunctionQuery scorer instances

Field Summary

Fields

Modifier and Type	Field	Description
(package private) final ValueSource	func

Constructor Summary

Constructors

Constructor	Description
FunctionQuery(ValueSource func)

Method Summary

Modifier and Type	Method	Description
Weight	createWeight(IndexSearcher searcher, ScoreMode scoreMode, float boost)	Expert: Constructs an appropriate Weight implementation for this query.
boolean	equals(Object other)	Returns true if o is equal to this.
ValueSource	getValueSource()
int	hashCode()	Override and implement query hash code properly in a subclass.
String	toString(String field)	Prints a user-readable version of this query.
void	visit(QueryVisitor visitor)	Recurse through the query tree, visiting any child queries.

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

classHash, rewrite, rewrite, sameClassAs, toString

Methods inherited from class java.lang.Object

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

Field Details

func

final ValueSource func

Constructor Details

FunctionQuery

public FunctionQuery(ValueSource func)

Parameters:

func - defines the function to be used for scoring

Method Details

getValueSource

public ValueSource getValueSource()

Returns:

The associated ValueSource

visit

public void visit(QueryVisitor visitor)

Description copied from class: Query

Recurse through the query tree, visiting any child queries.

Specified by:

visit in class Query

Parameters:

visitor - a QueryVisitor to be called by each query in the tree

createWeight

public Weight createWeight(IndexSearcher searcher,
 ScoreMode scoreMode,
 float boost)
                    throws 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

Parameters:

scoreMode - How the produced scorers will be consumed.

boost - The boost that is propagated by the parent queries.

Throws:

IOException

toString

public String toString(String field)

Prints a user-readable version of this query.

Specified by:

toString in class Query

equals

public boolean equals(Object other)

Returns true if o is equal to this.

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)