org.apache.lucene.analysis.standard

Class StandardTokenizer

java.lang.Object

org.apache.lucene.analysis.TokenStream

org.apache.lucene.analysis.Tokenizer

org.apache.lucene.analysis.standard.StandardTokenizer

public class StandardTokenizer
extends Tokenizer

A grammar-based tokenizer constructed with JFlex

This should be a good tokenizer for most European-language documents:

• Splits words at punctuation characters, removing punctuation. However, a dot that's not followed by whitespace is considered part of a token.
• Splits words at hyphens, unless there's a number in the token, in which case the whole token is interpreted as a product number and is not split.
• Recognizes email addresses and internet hostnames as one token.

Many applications have specific tokenizer needs. If this tokenizer does not suit your application, please consider copying this source code directory to your project and maintaining your own grammar-based tokenizer.

Field Summary

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

input

Constructor Summary

Constructors

Constructor and Description
StandardTokenizer(Reader input) Creates a new instance of the StandardTokenizer.
StandardTokenizer(Reader input, boolean replaceInvalidAcronym) Creates a new instance of the StandardTokenizer.

Method Summary

Methods

Modifier and Type	Method and Description
int	getMaxTokenLength()
boolean	isReplaceInvalidAcronym() Deprecated. Remove in 3.X and make true the only valid value
Token	next(Token result) Returns the next token in the stream, or null at EOS.
void	reset() Resets this stream to the beginning.
void	reset(Reader reader) Expert: Reset the tokenizer to a new reader.
void	setMaxTokenLength(int length) Set the max allowed token length.
void	setReplaceInvalidAcronym(boolean replaceInvalidAcronym) Deprecated. Remove in 3.X and make true the only valid value See https://issues.apache.org/jira/browse/LUCENE-1068

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

close

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

Constructor Detail

StandardTokenizer

public StandardTokenizer(Reader input)

Creates a new instance of the StandardTokenizer. Attaches the input to a newly created JFlex scanner.

StandardTokenizer

public StandardTokenizer(Reader input,
                 boolean replaceInvalidAcronym)

Creates a new instance of the StandardTokenizer. Attaches the input to the newly created JFlex scanner.

Parameters:

input - The input reader

replaceInvalidAcronym - Set to true to replace mischaracterized acronyms with HOST. See http://issues.apache.org/jira/browse/LUCENE-1068

Method Detail

setMaxTokenLength

public void setMaxTokenLength(int length)

Set the max allowed token length. Any token longer than this is skipped.

getMaxTokenLength

public int getMaxTokenLength()

See Also:

setMaxTokenLength(int)

next

public Token next(Token result)
           throws IOException

Description copied from class: TokenStream

Returns the next token in the stream, or null at EOS. When possible, the input Token should be used as the returned Token (this gives fastest tokenization performance), but this is not required and a new Token may be returned. Callers may re-use a single Token instance for successive calls to this method.

This implicitly defines a "contract" between consumers (callers of this method) and producers (implementations of this method that are the source for tokens):

• A consumer must fully consume the previously returned Token before calling this method again.
• A producer must call Token.clear() before setting the fields in it & returning it

Note that a TokenFilter is considered a consumer.

Overrides:

next in class TokenStream

Parameters:

result - a Token that may or may not be used to return

Returns:

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

Throws:

IOException

reset

public void reset()
           throws IOException

Description copied from class: TokenStream

Resets this stream to the beginning. This is an optional operation, so subclasses may or may not implement this method. Reset() is not needed for the standard indexing process. However, if the Tokens of a TokenStream are intended to be consumed more than once, it is necessary to implement reset().

Overrides:

reset in class TokenStream

Throws:

IOException

reset

public void reset(Reader reader)
           throws IOException

Description copied from class: Tokenizer

Expert: Reset the tokenizer to a new reader. Typically, an analyzer (in its reusableTokenStream method) will use this to re-use a previously created tokenizer.

Overrides:

reset in class Tokenizer

Throws:

IOException

isReplaceInvalidAcronym

public boolean isReplaceInvalidAcronym()

Deprecated. Remove in 3.X and make true the only valid value

Prior to https://issues.apache.org/jira/browse/LUCENE-1068, StandardTokenizer mischaracterized as acronyms tokens like www.abc.com when they should have been labeled as hosts instead.

Returns:

true if StandardTokenizer now returns these tokens as Hosts, otherwise false

setReplaceInvalidAcronym

public void setReplaceInvalidAcronym(boolean replaceInvalidAcronym)

Deprecated. Remove in 3.X and make true the only valid value See https://issues.apache.org/jira/browse/LUCENE-1068

Parameters:

replaceInvalidAcronym - Set to true to replace mischaracterized acronyms as HOST.