Class CharTokenizer

An abstract base class for simple, character-oriented tokenizers.

You must specify the required Lucene.Net.Util.LuceneVersion compatibility when creating CharTokenizer:

As of 3.1, CharTokenizer uses an int based API to normalize and detect token codepoints. See IsTokenChar(Int32) and Normalize(Int32) for details.

A new CharTokenizer API has been introduced with Lucene 3.1. This API moved from UTF-16 code units to UTF-32 codepoints to eventually add support for supplementary characters. The old char based API has been deprecated and should be replaced with the int based methods IsTokenChar(Int32) and Normalize(Int32).

As of Lucene 3.1 each CharTokenizer - constructor expects a Lucene.Net.Util.LuceneVersion argument. Based on the given Lucene.Net.Util.LuceneVersion either the new API or a backwards compatibility layer is used at runtime. For Lucene.Net.Util.LuceneVersion < 3.1 the backwards compatibility layer ensures correct behavior even for indexes build with previous versions of Lucene. If a Lucene.Net.Util.LuceneVersion >= 3.1 is used CharTokenizer requires the new API to be implemented by the instantiated class. Yet, the old char based API is not required anymore even if backwards compatibility must be preserved. CharTokenizer subclasses implementing the new API are fully backwards compatible if instantiated with Lucene.Net.Util.LuceneVersion < 3.1.

Note: If you use a subclass of CharTokenizer with Lucene.Net.Util.LuceneVersion >= 3.1 on an index build with a version < 3.1, created tokens might not be compatible with the terms in your index.

Inheritance

System.Object

Lucene.Net.Util.AttributeSource

Lucene.Net.Analysis.TokenStream

Lucene.Net.Analysis.Tokenizer

CharTokenizer

LetterTokenizer

WhitespaceTokenizer

IndicTokenizer

RussianLetterTokenizer

Implements

System.IDisposable

Inherited Members

Lucene.Net.Analysis.Tokenizer.m_input

Tokenizer.Dispose(Boolean)

Tokenizer.CorrectOffset(Int32)

Tokenizer.SetReader(TextReader)

Lucene.Net.Analysis.TokenStream.Dispose()

Lucene.Net.Util.AttributeSource.GetAttributeFactory()

Lucene.Net.Util.AttributeSource.GetAttributeClassesEnumerator()

Lucene.Net.Util.AttributeSource.GetAttributeImplsEnumerator()

Lucene.Net.Util.AttributeSource.AddAttributeImpl(Lucene.Net.Util.Attribute)

Lucene.Net.Util.AttributeSource.AddAttribute<T>()

Lucene.Net.Util.AttributeSource.HasAttributes

Lucene.Net.Util.AttributeSource.HasAttribute<T>()

Lucene.Net.Util.AttributeSource.GetAttribute<T>()

Lucene.Net.Util.AttributeSource.ClearAttributes()

Lucene.Net.Util.AttributeSource.CaptureState()

Lucene.Net.Util.AttributeSource.RestoreState(Lucene.Net.Util.AttributeSource.State)

Lucene.Net.Util.AttributeSource.GetHashCode()

AttributeSource.Equals(Object)

AttributeSource.ReflectAsString(Boolean)

Lucene.Net.Util.AttributeSource.ReflectWith(Lucene.Net.Util.IAttributeReflector)

Lucene.Net.Util.AttributeSource.CloneAttributes()

Lucene.Net.Util.AttributeSource.CopyTo(Lucene.Net.Util.AttributeSource)

Lucene.Net.Util.AttributeSource.ToString()

System.Object.Equals(System.Object, System.Object)

System.Object.GetType()

System.Object.MemberwiseClone()

System.Object.ReferenceEquals(System.Object, System.Object)

Namespace: Lucene.Net.Analysis.Util

Assembly: Lucene.Net.Analysis.Common.dll

Syntax

public abstract class CharTokenizer : Tokenizer, IDisposable

Constructors

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CharTokenizer(LuceneVersion, AttributeSource.AttributeFactory, TextReader)

Creates a new CharTokenizer instance

Declaration

public CharTokenizer(LuceneVersion matchVersion, AttributeSource.AttributeFactory factory, TextReader input)

Parameters

Type	Name	Description
Lucene.Net.Util.LuceneVersion	matchVersion	Lucene version to match
Lucene.Net.Util.AttributeSource.AttributeFactory	factory	the attribute factory to use for this Lucene.Net.Analysis.Tokenizer
System.IO.TextReader	input	the input to split up into tokens

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CharTokenizer(LuceneVersion, TextReader)

Creates a new CharTokenizer instance

Declaration

public CharTokenizer(LuceneVersion matchVersion, TextReader input)

Parameters

Type	Name	Description
Lucene.Net.Util.LuceneVersion	matchVersion	Lucene version to match
System.IO.TextReader	input	the input to split up into tokens

Methods

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End()

Declaration

public sealed override void End()

Overrides

Lucene.Net.Analysis.TokenStream.End()

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IncrementToken()

Declaration

public sealed override bool IncrementToken()

Returns

Type	Description
System.Boolean

Overrides

Lucene.Net.Analysis.TokenStream.IncrementToken()

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IsTokenChar(Int32)

Returns true iff a codepoint should be included in a token. This tokenizer generates as tokens adjacent sequences of codepoints which satisfy this predicate. Codepoints for which this is false are used to define token boundaries and are not included in tokens.

Declaration

protected abstract bool IsTokenChar(int c)

Parameters

Type	Name	Description
System.Int32	c

Returns

Type	Description
System.Boolean

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Normalize(Int32)

Called on each token character to normalize it before it is added to the token. The default implementation does nothing. Subclasses may use this to, e.g., lowercase tokens.

Declaration

protected virtual int Normalize(int c)

Parameters

Type	Name	Description
System.Int32	c

Returns

Type	Description
System.Int32

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Reset()

Declaration

public override void Reset()

Overrides

Lucene.Net.Analysis.Tokenizer.Reset()

Implements

System.IDisposable