Class CharFilter

Subclasses of CharFilter can be chained to filter a They can be used as with additional offset correction. Tokenizers will automatically use CorrectOffset(Int32) if a CharFilter subclass is used.

This class is abstract: at a minimum you must implement , transforming the input in some way from m_input, and Correct(Int32) to adjust the offsets to match the originals.

You can optionally provide more efficient implementations of additional methods like , but this is not required.

For examples and integration with Analyzer, see the Lucene.Net.Analysis namespace documentation.

Inheritance

System.Object

CharFilter

Namespace: Lucene.Net.Analysis

Assembly: Lucene.Net.dll

Syntax

public abstract class CharFilter : TextReader

Constructors

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CharFilter(TextReader)

Create a new CharFilter wrapping the provided reader.

Declaration

public CharFilter(TextReader input)

Parameters

Type	Name	Description
TextReader	input	a , can also be a CharFilter for chaining.

Fields

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m_input

The underlying character-input stream.

Declaration

protected readonly TextReader m_input

Field Value

Type	Description
TextReader

Properties

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IsMarkSupported

Tells whether this stream supports the Mark(Int32) operation. The default implementation always returns false. Subclasses should override this method.

LUCENENET specific. Moved here from the Reader class (in Java) so it can be overridden to provide reader buffering.

Declaration

public virtual bool IsMarkSupported { get; }

Property Value

Type	Description
System.Boolean	true if and only if this stream supports the mark operation.

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IsReady

Tells whether this stream is ready to be read.

True if the next is guaranteed not to block for input, false otherwise. Note that returning false does not guarantee that the next read will block.

LUCENENET specific. Moved here from the Reader class (in Java) so it can be overridden to provide reader buffering.

Declaration

public virtual bool IsReady { get; }

Property Value

Type	Description
System.Boolean

Methods

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Correct(Int32)

Subclasses override to correct the current offset.

Declaration

protected abstract int Correct(int currentOff)

Parameters

Type	Name	Description
System.Int32	currentOff	current offset

Returns

Type	Description
System.Int32	corrected offset

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CorrectOffset(Int32)

Chains the corrected offset through the input CharFilter(s).

Declaration

public int CorrectOffset(int currentOff)

Parameters

Type	Name	Description
System.Int32	currentOff

Returns

Type	Description
System.Int32

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Dispose(Boolean)

Closes the underlying input stream.

NOTE: The default implementation closes the input , so be sure to call base.Dispose(disposing) when overriding this method.

Declaration

protected override void Dispose(bool disposing)

Parameters

Type	Name	Description
System.Boolean	disposing

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Mark(Int32)

Marks the present position in the stream. Subsequent calls to Reset() will attempt to reposition the stream to this point. Not all character-input streams support the Mark(Int32) operation.

LUCENENET specific. Moved here from the Reader class (in Java) so it can be overridden to provide reader buffering.

Declaration

public virtual void Mark(int readAheadLimit)

Parameters

Type	Name	Description
System.Int32	readAheadLimit	Limit on the number of characters that may be read while still preserving the mark. After reading this many characters, attempting to reset the stream may fail.

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Read()

Declaration

public override int Read()

Returns

Type	Description
System.Int32

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Read(Char[], Int32, Int32)

Declaration

public abstract override int Read(char[] buffer, int index, int count)

Parameters

Type	Name	Description
System.Char[]	buffer
System.Int32	index
System.Int32	count

Returns

Type	Description
System.Int32

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Reset()

LUCENENET specific. Moved here from the Reader class (in Java) so it can be overridden to provide reader buffering.

Declaration

public virtual void Reset()

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Skip(Int32)

Skips characters. This method will block until some characters are available, an I/O error occurs, or the end of the stream is reached.

LUCENENET specific. Moved here from the Reader class (in Java) so it can be overridden to provide reader buffering.

Declaration

public virtual long Skip(int n)

Parameters

Type	Name	Description
System.Int32	n	The number of characters to skip

Returns

Type	Description
System.Int64	The number of characters actually skipped