org.apache.lucene.analysis.ngram
Class EdgeNGramTokenizer

java.lang.Object
  org.apache.lucene.analysis.TokenStream
      org.apache.lucene.analysis.Tokenizer
          org.apache.lucene.analysis.ngram.EdgeNGramTokenizer

public class EdgeNGramTokenizer
extends Tokenizer

Tokenizes the input from an edge into n-grams of given size(s). This tokenizer create n-grams from the beginning edge or ending edge of a input token. MaxGram can't be larger than 1024 because of limitation.

Nested Class Summary

static class

EdgeNGramTokenizer.Side Specifies which side of the input the n-gram should be generated from

Field Summary

static int	DEFAULT_MAX_GRAM_SIZE
static int	DEFAULT_MIN_GRAM_SIZE
static EdgeNGramTokenizer.Side	DEFAULT_SIDE

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

input

Constructor Summary

EdgeNGramTokenizer(Reader input, EdgeNGramTokenizer.Side side, int minGram, int maxGram)
Creates EdgeNGramTokenizer that can generate n-grams in the sizes of the given range

EdgeNGramTokenizer(Reader input, String sideLabel, int minGram, int maxGram)
Creates EdgeNGramTokenizer that can generate n-grams in the sizes of the given range

Method Summary

Token

next(Token reusableToken) Returns the next token in the stream, or null at EOS.

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

close, reset

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

next, reset

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 EdgeNGramTokenizer.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

EdgeNGramTokenizer

public EdgeNGramTokenizer(Reader input,
                          EdgeNGramTokenizer.Side side,
                          int minGram,
                          int maxGram)

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

Parameters:

input - Reader holding the input to be tokenized

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

minGram - the smallest n-gram to generate

maxGram - the largest n-gram to generate

EdgeNGramTokenizer

public EdgeNGramTokenizer(Reader input,
                          String sideLabel,
                          int minGram,
                          int maxGram)

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

Parameters:

input - Reader holding the input to be tokenized

sideLabel - the name of the EdgeNGramTokenizer.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 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:

IOException