Class FilteredQuery

A query that applies a filter to the results of another query.

Note: the bits are retrieved from the filter each time this query is used in a search - use a CachingWrapperFilter to avoid regenerating the bits every time.

@since 1.4
Inheritance
object
Query
FilteredQuery
Inherited Members
Namespace: Lucene.Net.Search
Assembly: Lucene.Net.dll
Syntax
public class FilteredQuery : Query

Constructors

FilteredQuery(Query, Filter)

Constructs a new query which applies a filter to the results of the original query. GetDocIdSet(AtomicReaderContext, IBits) will be called every time this query is used in a search.

Declaration
public FilteredQuery(Query query, Filter filter)
Parameters
Type Name Description
Query query

Query to be filtered, cannot be null.
Filter filter

Filter to apply to query results, cannot be null.
See Also

FilteredQuery(Query, Filter, FilterStrategy)

Expert: Constructs a new query which applies a filter to the results of the original query. GetDocIdSet(AtomicReaderContext, IBits) will be called every time this query is used in a search.

Declaration
public FilteredQuery(Query query, Filter filter, FilteredQuery.FilterStrategy strategy)
Parameters
Type Name Description
Query query

Query to be filtered, cannot be null.
Filter filter

Filter to apply to query results, cannot be null.
FilteredQuery.FilterStrategy strategy

A filter strategy used to create a filtered scorer.
See Also

Fields

LEAP_FROG_FILTER_FIRST_STRATEGY

A filter strategy that uses a "leap-frog" approach (also called "zig-zag join"). The scorer and the filter take turns trying to advance to each other's next matching document, often jumping past the target document. When both land on the same document, it's collected.

Note: this strategy uses the filter to lead the iteration.

Declaration
public static readonly FilteredQuery.FilterStrategy LEAP_FROG_FILTER_FIRST_STRATEGY
Field Value
Type Description
FilteredQuery.FilterStrategy
See Also

LEAP_FROG_QUERY_FIRST_STRATEGY

A filter strategy that uses a "leap-frog" approach (also called "zig-zag join"). The scorer and the filter take turns trying to advance to each other's next matching document, often jumping past the target document. When both land on the same document, it's collected.

Note: this strategy uses the query to lead the iteration.

Declaration
public static readonly FilteredQuery.FilterStrategy LEAP_FROG_QUERY_FIRST_STRATEGY
Field Value
Type Description
FilteredQuery.FilterStrategy
See Also

QUERY_FIRST_FILTER_STRATEGY

A filter strategy that advances the Query or rather its Scorer first and consults the filter DocIdSet for each matched document.

Note: this strategy requires a Bits to return a non-null value. Otherwise this strategy falls back to LEAP_FROG_QUERY_FIRST_STRATEGY

Use this strategy if the filter computation is more expensive than document scoring or if the filter has a linear running time to compute the next matching doc like exact geo distances.

Declaration
public static readonly FilteredQuery.FilterStrategy QUERY_FIRST_FILTER_STRATEGY
Field Value
Type Description
FilteredQuery.FilterStrategy
See Also

RANDOM_ACCESS_FILTER_STRATEGY

A FilteredQuery.FilterStrategy that conditionally uses a random access filter if the given DocIdSet supports random access (returns a non-null value from Bits) and UseRandomAccess(IBits, int) returns true. Otherwise this strategy falls back to a "zig-zag join" ( LEAP_FROG_FILTER_FIRST_STRATEGY) strategy.

Note: this strategy is the default strategy in FilteredQuery

Declaration
public static readonly FilteredQuery.FilterStrategy RANDOM_ACCESS_FILTER_STRATEGY
Field Value
Type Description
FilteredQuery.FilterStrategy
See Also

Properties

Filter

Returns this FilteredQuery's filter

Declaration
public Filter Filter { get; }
Property Value
Type Description
Filter
See Also

Query

Returns this FilteredQuery's (unfiltered) Query

Declaration
public Query Query { get; }
Property Value
Type Description
Query
See Also

Strategy

Returns this FilteredQuery's FilteredQuery.FilterStrategy

Declaration
public virtual FilteredQuery.FilterStrategy Strategy { get; }
Property Value
Type Description
FilteredQuery.FilterStrategy
See Also

Methods

CreateWeight(IndexSearcher)

Returns a Weight that applies the filter to the enclosed query's Weight. this is accomplished by overriding the Scorer returned by the Weight.

Declaration
public override Weight CreateWeight(IndexSearcher searcher)
Parameters
Type Name Description
IndexSearcher searcher
Returns
Type Description
Weight
Overrides
See Also

Equals(object)

Returns true if o is equal to this.

Declaration
public override bool Equals(object o)
Parameters
Type Name Description
object o
Returns
Type Description
bool
Overrides
See Also

ExtractTerms(ISet<Term>)

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

Declaration
public override void ExtractTerms(ISet<Term> terms)
Parameters
Type Name Description
ISet<Term> terms
Overrides
Exceptions
Type Condition
InvalidOperationException

If this query is not yet rewritten
See Also

GetHashCode()

Returns a hash code value for this object.

Declaration
public override int GetHashCode()
Returns
Type Description
int
Overrides
See Also

Rewrite(IndexReader)

Rewrites the query. If the wrapped is an instance of MatchAllDocsQuery it returns a ConstantScoreQuery. Otherwise it returns a new FilteredQuery wrapping the rewritten query.

Declaration
public override Query Rewrite(IndexReader reader)
Parameters
Type Name Description
IndexReader reader
Returns
Type Description
Query
Overrides
See Also

ToString(string)

Prints a user-readable version of this query.

Declaration
public override string ToString(string s)
Parameters
Type Name Description
string s
Returns
Type Description
string
Overrides
See Also

See Also