Class CJKWidthFilter

A Lucene.Net.Analysis.TokenFilter that normalizes CJK width differences:

• Folds fullwidth ASCII variants into the equivalent basic latin
• Folds halfwidth Katakana variants into the equivalent kana

NOTE: this filter can be viewed as a (practical) subset of NFKC/NFKD Unicode normalization. See the normalization support in the ICU package for full normalization.

Inheritance

object

AttributeSource

TokenStream

TokenFilter

CJKWidthFilter

Implements

IDisposable

Inherited Members

TokenFilter.End()

TokenFilter.Reset()

TokenStream.Dispose()

AttributeSource.GetAttributeFactory()

AttributeSource.GetAttributeClassesEnumerator()

AttributeSource.GetAttributeImplsEnumerator()

AttributeSource.AddAttributeImpl(Attribute)

AttributeSource.AddAttribute<T>()

AttributeSource.HasAttributes

AttributeSource.HasAttribute<T>()

AttributeSource.GetAttribute<T>()

AttributeSource.ClearAttributes()

AttributeSource.CaptureState()

AttributeSource.RestoreState(AttributeSource.State)

AttributeSource.GetHashCode()

AttributeSource.Equals(object)

AttributeSource.ReflectAsString(bool)

AttributeSource.ReflectWith(IAttributeReflector)

AttributeSource.CloneAttributes()

AttributeSource.CopyTo(AttributeSource)

AttributeSource.ToString()

object.Equals(object, object)

object.GetType()

object.ReferenceEquals(object, object)

Namespace: Lucene.Net.Analysis.Cjk

Assembly: Lucene.Net.Analysis.Common.dll

Syntax

public sealed class CJKWidthFilter : TokenFilter, IDisposable

Constructors

CJKWidthFilter(TokenStream)

A Lucene.Net.Analysis.TokenFilter that normalizes CJK width differences:

• Folds fullwidth ASCII variants into the equivalent basic latin
• Folds halfwidth Katakana variants into the equivalent kana

NOTE: this filter can be viewed as a (practical) subset of NFKC/NFKD Unicode normalization. See the normalization support in the ICU package for full normalization.

Declaration

public CJKWidthFilter(TokenStream input)

Parameters

Type	Name	Description
TokenStream	input

Methods

IncrementToken()

Consumers (i.e., Lucene.Net.Index.IndexWriter) use this method to advance the stream to the next token. Implementing classes must implement this method and update the appropriate Lucene.Net.Util.IAttributes with the attributes of the next token.

The producer must make no assumptions about the attributes after the method has been returned: the caller may arbitrarily change it. If the producer needs to preserve the state for subsequent calls, it can use Lucene.Net.Util.AttributeSource.CaptureState() to create a copy of the current attribute state.

this method is called for every token of a document, so an efficient implementation is crucial for good performance. To avoid calls to Lucene.Net.Util.AttributeSource.AddAttribute<T>() and Lucene.Net.Util.AttributeSource.GetAttribute<T>(), references to all Lucene.Net.Util.IAttributes that this stream uses should be retrieved during instantiation.

To ensure that filters and consumers know which attributes are available, the attributes must be added during instantiation. Filters and consumers are not required to check for availability of attributes in Lucene.Net.Analysis.TokenStream.IncrementToken().

Declaration

public override bool IncrementToken()

Returns

Type	Description
bool	false for end of stream; true otherwise

Overrides

Lucene.Net.Analysis.TokenStream.IncrementToken()

Implements

IDisposable