Module org.apache.lucene.queries

Package org.apache.lucene.queries.function

Class FunctionMatchQuery

java.lang.Object

org.apache.lucene.search.Query

org.apache.lucene.queries.function.FunctionMatchQuery

public final class FunctionMatchQuery
extends Query

A query that retrieves all documents with a DoubleValues value matching a predicate

This query works by a linear scan of the index, and is best used in conjunction with other queries that can restrict the number of documents visited

Field Summary

Fields

Modifier and Type	Field	Description
(package private) static final float	DEFAULT_MATCH_COST
private final DoublePredicate	filter
private final float	matchCost
private final DoubleValuesSource	source

Constructor Summary

Constructors

Constructor	Description
FunctionMatchQuery(DoubleValuesSource source, DoublePredicate filter)	Create a FunctionMatchQuery with default TwoPhaseIterator matchCost - DEFAULT_MATCH_COST = 100.0f
FunctionMatchQuery(DoubleValuesSource source, DoublePredicate filter, float matchCost)	Create a FunctionMatchQuery

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 o)	Override and implement query instance equivalence properly in a subclass.
int	hashCode()	Override and implement query hash code properly in a subclass.
String	toString(String field)	Prints a query to a string, with field 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, rewrite, rewrite, sameClassAs, toString

Methods inherited from class java.lang.Object

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

Field Details

DEFAULT_MATCH_COST

static final float DEFAULT_MATCH_COST

See Also:

• Constant Field Values

source

private final DoubleValuesSource source

filter

private final DoublePredicate filter

matchCost

private final float matchCost

Constructor Details

FunctionMatchQuery

public FunctionMatchQuery(DoubleValuesSource source,
 DoublePredicate filter)

Create a FunctionMatchQuery with default TwoPhaseIterator matchCost - DEFAULT_MATCH_COST = 100.0f

Parameters:

source - a DoubleValuesSource to use for values

filter - the predicate to match against

FunctionMatchQuery

public FunctionMatchQuery(DoubleValuesSource source,
 DoublePredicate filter,
 float matchCost)

Create a FunctionMatchQuery

Parameters:

source - a DoubleValuesSource to use for values

filter - the predicate to match against

matchCost - to be returned by TwoPhaseIterator.matchCost()

Method Details

toString

public String toString(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

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

equals

public boolean equals(Object o)

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 to those of the 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)