Class JapaneseKatakanaStemFilter

A Lucene.Net.Analysis.TokenFilter that normalizes common katakana spelling variations ending in a long sound character by removing this character (U+30FC). Only katakana words longer than a minimum length are stemmed (default is four).

Inheritance

object

AttributeSource

TokenStream

TokenFilter

JapaneseKatakanaStemFilter

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.Ja

Assembly: Lucene.Net.Analysis.Kuromoji.dll

Syntax

public sealed class JapaneseKatakanaStemFilter : TokenFilter, IDisposable

Remarks

Note that only full-width katakana characters are supported. Please use a Lucene.Net.Analysis.Cjk.CJKWidthFilter to convert half-width katakana to full-width before using this filter.

In order to prevent terms from being stemmed, use an instance of Lucene.Net.Analysis.Miscellaneous.SetKeywordMarkerFilter or a custom Lucene.Net.Analysis.TokenFilter that sets the Lucene.Net.Analysis.TokenAttributes.IKeywordAttribute before this Lucene.Net.Analysis.TokenStream.

Constructors

JapaneseKatakanaStemFilter(TokenStream)

Declaration

public JapaneseKatakanaStemFilter(TokenStream input)

Parameters

Type	Name	Description
TokenStream	input

Remarks

Note that only full-width katakana characters are supported. Please use a Lucene.Net.Analysis.Cjk.CJKWidthFilter to convert half-width katakana to full-width before using this filter.

JapaneseKatakanaStemFilter(TokenStream, int)

Declaration

public JapaneseKatakanaStemFilter(TokenStream input, int minimumLength)

Parameters

Type	Name	Description
TokenStream	input
int	minimumLength

Remarks

Note that only full-width katakana characters are supported. Please use a Lucene.Net.Analysis.Cjk.CJKWidthFilter to convert half-width katakana to full-width before using this filter.

Fields

DEFAULT_MINIMUM_LENGTH

Declaration

public const int DEFAULT_MINIMUM_LENGTH = 4

Field Value

Type	Description
int

Remarks

Note that only full-width katakana characters are supported. Please use a Lucene.Net.Analysis.Cjk.CJKWidthFilter to convert half-width katakana to full-width before using this filter.

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()

Remarks

Note that only full-width katakana characters are supported. Please use a Lucene.Net.Analysis.Cjk.CJKWidthFilter to convert half-width katakana to full-width before using this filter.

Implements

IDisposable