Class FilteredDocIdSet

Abstract decorator class for a DocIdSet implementation that provides on-demand filtering/validation mechanism on a given DocIdSet.

Technically, this same functionality could be achieved with ChainedFilter (under queries/), however the benefit of this class is it never materializes the full bitset for the filter. Instead, the Match(int) method is invoked on-demand, per docID visited during searching. If you know few docIDs will be visited, and the logic behind Match(int) is relatively costly, this may be a better way to filter than ChainedFilter.

Inheritance
object
DocIdSet
FilteredDocIdSet
BitsFilteredDocIdSet
Inherited Members
Namespace: Lucene.Net.Search
Assembly: Lucene.Net.dll
Syntax
public abstract class FilteredDocIdSet : DocIdSet

Constructors

FilteredDocIdSet(DocIdSet)

Constructor.

Declaration
protected FilteredDocIdSet(DocIdSet innerSet)
Parameters
Type Name Description
DocIdSet innerSet

Underlying DocIdSet
See Also

Properties

Bits

Optionally provides a IBits interface for random access to matching documents.

Declaration
public override IBits Bits { get; }
Property Value
Type Description
IBits

null, if this DocIdSet does not support random access. In contrast to GetIterator(), a return value of nulldoes not imply that no documents match the filter! The default implementation does not provide random access, so you only need to implement this method if your DocIdSet can guarantee random access to every docid in O(1) time without external disk access (as IBits interface cannot throw IOException). This is generally true for bit sets like FixedBitSet, which return itself if they are used as DocIdSet.
Overrides
See Also

IsCacheable

This DocIdSet implementation is cacheable if the inner set is cacheable.

Declaration
public override bool IsCacheable { get; }
Property Value
Type Description
bool
Overrides
See Also

Methods

GetIterator()

Implementation of the contract to build a DocIdSetIterator.

Declaration
public override DocIdSetIterator GetIterator()
Returns
Type Description
DocIdSetIterator
Overrides
See Also

Match(int)

Validation method to determine whether a docid should be in the result set.

Declaration
protected abstract bool Match(int docid)
Parameters
Type Name Description
int docid

docid to be tested
Returns
Type Description
bool

true if input docid should be in the result set, false otherwise.
See Also

See Also