Class CachingWrapperFilter

Wraps another Filter's result and caches it. The purpose is to allow filters to simply filter, and then wrap with this class to add caching.

Inheritance
object
Filter
CachingWrapperFilter
Inherited Members
Namespace: Lucene.Net.Search
Assembly: Lucene.Net.dll
Syntax
public class CachingWrapperFilter : Filter

Constructors

CachingWrapperFilter(Filter)

Wraps another filter's result and caches it.

Declaration
public CachingWrapperFilter(Filter filter)
Parameters
Type Name Description
Filter filter

Filter to cache results of

Fields

EMPTY_DOCIDSET

An empty DocIdSet instance

Declaration
protected static readonly DocIdSet EMPTY_DOCIDSET
Field Value
Type Description
DocIdSet

Properties

Filter

Gets the contained filter.

Declaration
public virtual Filter Filter { get; }
Property Value
Type Description
Filter

the contained filter.

Methods

CacheImpl(DocIdSetIterator, AtomicReader)

Default cache implementation: uses WAH8DocIdSet.

Declaration
protected virtual DocIdSet CacheImpl(DocIdSetIterator iterator, AtomicReader reader)
Parameters
Type Name Description
DocIdSetIterator iterator
AtomicReader reader
Returns
Type Description
DocIdSet

DocIdSetToCache(DocIdSet, AtomicReader)

Provide the DocIdSet to be cached, using the DocIdSet provided by the wrapped Filter.

This implementation returns the given DocIdSet, if IsCacheable returns true, else it calls CacheImpl(DocIdSetIterator, AtomicReader)

Note: this method returns EMPTY_DOCIDSET if the given docIdSet is null or if GetIterator() return null. The empty instance is use as a placeholder in the cache instead of the null value.
Declaration
protected virtual DocIdSet DocIdSetToCache(DocIdSet docIdSet, AtomicReader reader)
Parameters
Type Name Description
DocIdSet docIdSet
AtomicReader reader
Returns
Type Description
DocIdSet

Equals(object)

Determines whether the specified object is equal to the current object.

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

true if the specified object is equal to the current object; otherwise, false.
Overrides

GetDocIdSet(AtomicReaderContext, IBits)

Creates a DocIdSet enumerating the documents that should be permitted in search results. NOTE:null can be returned if no documents are accepted by this Filter.

Note: this method will be called once per segment in the index during searching. The returned DocIdSet must refer to document IDs for that segment, not for the top-level reader.
Declaration
public override DocIdSet GetDocIdSet(AtomicReaderContext context, IBits acceptDocs)
Parameters
Type Name Description
AtomicReaderContext context

a AtomicReaderContext instance opened on the index currently searched on. Note, it is likely that the provided reader info does not represent the whole underlying index i.e. if the index has more than one segment the given reader only represents a single segment. The provided context is always an atomic context, so you can call Fields on the context's reader, for example.
IBits acceptDocs

IBits that represent the allowable docs to match (typically deleted docs but possibly filtering other documents)
Returns
Type Description
DocIdSet

A DocIdSet that provides the documents which should be permitted or prohibited in search results. NOTE:null should be returned if the filter doesn't accept any documents otherwise internal optimization might not apply in the case an emptyDocIdSet is returned.
Overrides

GetHashCode()

Serves as the default hash function.

Declaration
public override int GetHashCode()
Returns
Type Description
int

A hash code for the current object.
Overrides

GetSizeInBytes()

Returns total byte size used by cached filters.

Declaration
public virtual long GetSizeInBytes()
Returns
Type Description
long

ToString()

Returns a string that represents the current object.

Declaration
public override string ToString()
Returns
Type Description
string

A string that represents the current object.
Overrides