Class EdgeNGramTokenFilter

Tokenizes the given token into n-grams of given size(s).

This Lucene.Net.Analysis.TokenFilter create n-grams from the beginning edge or ending edge of a input token.

As of Lucene 4.4, this filter does not support BACK (you can use ReverseStringFilter up-front and afterward to get the same behavior), handles supplementary characters correctly and does not update offsets anymore.

Inheritance

object

AttributeSource

TokenStream

TokenFilter

EdgeNGramTokenFilter

Implements

IDisposable

Inherited Members

TokenFilter.End()

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.NGram

Assembly: Lucene.Net.Analysis.Common.dll

Syntax

public sealed class EdgeNGramTokenFilter : TokenFilter, IDisposable

Constructors

EdgeNGramTokenFilter(LuceneVersion, TokenStream, Side, int, int)

Creates EdgeNGramTokenFilter that can generate n-grams in the sizes of the given range

Declaration

[Obsolete]
public EdgeNGramTokenFilter(LuceneVersion version, TokenStream input, EdgeNGramTokenFilter.Side side, int minGram, int maxGram)

Parameters

Type	Name	Description
LuceneVersion	version	the Lucene match version - See Lucene.Net.Util.LuceneVersion
TokenStream	input	Lucene.Net.Analysis.TokenStream holding the input to be tokenized
EdgeNGramTokenFilter.Side	side	the EdgeNGramTokenFilter.Side from which to chop off an n-gram
int	minGram	the smallest n-gram to generate
int	maxGram	the largest n-gram to generate

EdgeNGramTokenFilter(LuceneVersion, TokenStream, int, int)

Creates EdgeNGramTokenFilter that can generate n-grams in the sizes of the given range

Declaration

public EdgeNGramTokenFilter(LuceneVersion version, TokenStream input, int minGram, int maxGram)

Parameters

Type	Name	Description
LuceneVersion	version	the Lucene match version - See Lucene.Net.Util.LuceneVersion
TokenStream	input	Lucene.Net.Analysis.TokenStream holding the input to be tokenized
int	minGram	the smallest n-gram to generate
int	maxGram	the largest n-gram to generate

EdgeNGramTokenFilter(LuceneVersion, TokenStream, string, int, int)

Creates EdgeNGramTokenFilter that can generate n-grams in the sizes of the given range

Declaration

[Obsolete]
public EdgeNGramTokenFilter(LuceneVersion version, TokenStream input, string sideLabel, int minGram, int maxGram)

Parameters

Type	Name	Description
LuceneVersion	version	the Lucene match version - See Lucene.Net.Util.LuceneVersion
TokenStream	input	Lucene.Net.Analysis.TokenStream holding the input to be tokenized
string	sideLabel	the name of the EdgeNGramTokenFilter.Side from which to chop off an n-gram
int	minGram	the smallest n-gram to generate
int	maxGram	the largest n-gram to generate

Fields

DEFAULT_MAX_GRAM_SIZE

Tokenizes the given token into n-grams of given size(s).

This Lucene.Net.Analysis.TokenFilter create n-grams from the beginning edge or ending edge of a input token.

As of Lucene 4.4, this filter does not support BACK (you can use ReverseStringFilter up-front and afterward to get the same behavior), handles supplementary characters correctly and does not update offsets anymore.

Declaration

public const int DEFAULT_MAX_GRAM_SIZE = 1

Field Value

Type	Description
int

DEFAULT_MIN_GRAM_SIZE

Tokenizes the given token into n-grams of given size(s).

This Lucene.Net.Analysis.TokenFilter create n-grams from the beginning edge or ending edge of a input token.

As of Lucene 4.4, this filter does not support BACK (you can use ReverseStringFilter up-front and afterward to get the same behavior), handles supplementary characters correctly and does not update offsets anymore.

Declaration

public const int DEFAULT_MIN_GRAM_SIZE = 1

Field Value

Type	Description
int

DEFAULT_SIDE

Tokenizes the given token into n-grams of given size(s).

This Lucene.Net.Analysis.TokenFilter create n-grams from the beginning edge or ending edge of a input token.

As of Lucene 4.4, this filter does not support BACK (you can use ReverseStringFilter up-front and afterward to get the same behavior), handles supplementary characters correctly and does not update offsets anymore.

Declaration

public const EdgeNGramTokenFilter.Side DEFAULT_SIDE = FRONT

Field Value

Type	Description
EdgeNGramTokenFilter.Side

Methods

GetSide(string)

Get the appropriate EdgeNGramTokenFilter.Side from a string

Declaration

public static EdgeNGramTokenFilter.Side GetSide(string sideName)

Parameters

Type	Name	Description
string	sideName

Returns

Type	Description
EdgeNGramTokenFilter.Side

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 sealed bool IncrementToken()

Returns

Type	Description
bool	false for end of stream; true otherwise

Overrides

Lucene.Net.Analysis.TokenStream.IncrementToken()

Reset()

This method is called by a consumer before it begins consumption using Lucene.Net.Analysis.TokenStream.IncrementToken().

Resets this stream to a clean state. Stateful implementations must implement this method so that they can be reused, just as if they had been created fresh.

If you override this method, always call base.Reset(), otherwise some internal state will not be correctly reset (e.g., Lucene.Net.Analysis.Tokenizer will throw InvalidOperationException on further usage).

Declaration

public override void Reset()

Overrides

Lucene.Net.Analysis.TokenFilter.Reset()

Remarks

NOTE: The default implementation chains the call to the input Lucene.Net.Analysis.TokenStream, so be sure to call base.Reset() when overriding this method.

Implements

IDisposable