org.apache.lucene.analysis.ngram

Class EdgeNGramTokenFilter

java.lang.Object

org.apache.lucene.analysis.TokenStream

org.apache.lucene.analysis.TokenFilter

org.apache.lucene.analysis.ngram.EdgeNGramTokenFilter

public class EdgeNGramTokenFilter
extends TokenFilter

Tokenizes the given token into n-grams of given size(s). This filter create n-grams from the beginning edge or ending edge of a input token.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	EdgeNGramTokenFilter.Side Specifies which side of the input the n-gram should be generated from

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_MAX_GRAM_SIZE
static int	DEFAULT_MIN_GRAM_SIZE
static EdgeNGramTokenFilter.Side	DEFAULT_SIDE

Fields inherited from class org.apache.lucene.analysis.TokenFilter

input

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	EdgeNGramTokenFilter(TokenStream input)
	EdgeNGramTokenFilter(TokenStream input, EdgeNGramTokenFilter.Side side, int minGram, int maxGram) Creates EdgeNGramTokenFilter that can generate n-grams in the sizes of the given range
	EdgeNGramTokenFilter(TokenStream input, java.lang.String sideLabel, int minGram, int maxGram) Creates EdgeNGramTokenFilter that can generate n-grams in the sizes of the given range

Method Summary

Methods

Modifier and Type	Method and Description
Token	next(Token reusableToken) Returns the next token in the stream, or null at EOS.

Methods inherited from class org.apache.lucene.analysis.TokenFilter

close, reset

Methods inherited from class org.apache.lucene.analysis.TokenStream

next

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DEFAULT_SIDE

public static final EdgeNGramTokenFilter.Side DEFAULT_SIDE

DEFAULT_MAX_GRAM_SIZE

public static final int DEFAULT_MAX_GRAM_SIZE

See Also:

Constant Field Values

DEFAULT_MIN_GRAM_SIZE

public static final int DEFAULT_MIN_GRAM_SIZE

See Also:

Constant Field Values

Constructor Detail

EdgeNGramTokenFilter

protected EdgeNGramTokenFilter(TokenStream input)

EdgeNGramTokenFilter

public EdgeNGramTokenFilter(TokenStream input,
                    EdgeNGramTokenFilter.Side side,
                    int minGram,
                    int maxGram)

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

Parameters:

input - TokenStream holding the input to be tokenized

side - the EdgeNGramTokenFilter.Side from which to chop off an n-gram

minGram - the smallest n-gram to generate

maxGram - the largest n-gram to generate

EdgeNGramTokenFilter

public EdgeNGramTokenFilter(TokenStream input,
                    java.lang.String sideLabel,
                    int minGram,
                    int maxGram)

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

Parameters:

input - TokenStream holding the input to be tokenized

sideLabel - the name of the EdgeNGramTokenFilter.Side from which to chop off an n-gram

minGram - the smallest n-gram to generate

maxGram - the largest n-gram to generate

Method Detail

next

public final Token next(Token reusableToken)
                 throws java.io.IOException

Returns the next token in the stream, or null at EOS.

Overrides:

next in class TokenStream

Parameters:

reusableToken - a Token that may or may not be used to return; this parameter should never be null (the callee is not required to check for null before using it, but it is a good idea to assert that it is not null.)

Returns:

next token in the stream or null if end-of-stream was hit

Throws:

java.io.IOException