Lucene.Net.Search.BoostingQuery Class Reference

The BoostingQuery class can be used to effectively demote results that match a given query. Unlike the "NOT" clause, this still selects documents that contain undesirable terms, but reduces their overall score: More...

Inherits Lucene.Net.Search.Query.

Public Member Functions
	BoostingQuery (Query match, Query context, float boost)
override Query	Rewrite (IndexReader reader)
	Expert: called to re-write queries into primitive queries. For example, a PrefixQuery will be rewritten into a BooleanQuery that consists of TermQuerys.
override int	GetHashCode ()
override bool	Equals (Object obj)
override String	ToString (String field)
Public Member Functions inherited from Lucene.Net.Search.Query
abstract System.String	ToString (System.String field)
	Prints a query to a string, with field assumed to be the default field and omitted. The representation used is one that is supposed to be readable by QueryParser. However, there are the following limitations: If the query was created by the parser, the printed representation may not be exactly what was parsed. For example, characters that need to be escaped will be represented without the required backslash. Some of the more complicated queries (e.g. span queries) don't have a representation that can be parsed by QueryParser.
override System.String	ToString ()
	Prints a query to a string.
virtual Weight	CreateWeight (Searcher searcher)
	Expert: Constructs an appropriate Weight implementation for this query.
virtual Weight	Weight (Searcher searcher)
	Expert: Constructs and initializes a Weight for a top-level query.
virtual Query	Combine (Query[] queries)
	Expert: called when re-writing queries under MultiSearcher.
virtual void	ExtractTerms (System.Collections.Generic.ISet< Term > terms)
	Expert: adds all terms occuring in this query to the terms set. Only works if this query is in its rewritten form.
virtual Similarity	GetSimilarity (Searcher searcher)
	Expert: Returns the Similarity implementation to be used for this query. Subclasses may override this method to specify their own Similarity implementation, perhaps one that delegates through that of the Searcher. By default the Searcher's Similarity implementation is returned.
virtual System.Object	Clone ()
	Returns a clone of this query.
override int	GetHashCode ()
override bool	Equals (System.Object obj)

Additional Inherited Members
Static Public Member Functions inherited from Lucene.Net.Search.Query
static Query	MergeBooleanQueries (params BooleanQuery[] queries)
	Expert: merges the clauses of a set of BooleanQuery's into a single BooleanQuery.
Properties inherited from Lucene.Net.Search.Query
virtual float	Boost [get, set]
	Gets or sets the boost for this query clause to b. Documents matching this clause will (in addition to the normal weightings) have their score multiplied by b. The boost is 1.0 by default.

Detailed Description

The BoostingQuery class can be used to effectively demote results that match a given query. Unlike the "NOT" clause, this still selects documents that contain undesirable terms, but reduces their overall score:

     Query balancedQuery = new BoostingQuery(positiveQuery, negativeQuery, 0.01f);
 

In this scenario the positiveQuery contains the mandatory, desirable criteria which is used to select all matching documents, and the negativeQuery contains the undesirable elements which are simply used to lessen the scores. Documents that match the negativeQuery have their score multiplied by the supplied "boost" parameter, so this should be less than 1 to achieve a demoting effect

This code was originally made available here: mailing list and is documented here: Documentation

Definition at line 45 of file BoostingQuery.cs.

Constructor & Destructor Documentation

Lucene.Net.Search.BoostingQuery.BoostingQuery	(	Query	match,
		Query	context,
		float	boost
	)

Definition at line 51 of file BoostingQuery.cs.

Member Function Documentation

override bool Lucene.Net.Search.BoostingQuery.Equals

(

Object

obj

)

Definition at line 120 of file BoostingQuery.cs.

override int Lucene.Net.Search.BoostingQuery.GetHashCode

(

)

Definition at line 110 of file BoostingQuery.cs.

override Query Lucene.Net.Search.BoostingQuery.Rewrite ( IndexReader  reader )

virtual

Expert: called to re-write queries into primitive queries. For example, a PrefixQuery will be rewritten into a BooleanQuery that consists of TermQuerys.

Reimplemented from Lucene.Net.Search.Query.

Definition at line 60 of file BoostingQuery.cs.

override String Lucene.Net.Search.BoostingQuery.ToString

(

String

field

)

Definition at line 148 of file BoostingQuery.cs.

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The documentation for this class was generated from the following file:

• contrib/Queries/BoostingQuery.cs