org.apache.lucene.analysis.cjk
Class CJKTokenizer

java.lang.Object
  extended by org.apache.lucene.util.AttributeSource
      extended by org.apache.lucene.analysis.TokenStream
          extended by org.apache.lucene.analysis.Tokenizer
              extended by org.apache.lucene.analysis.cjk.CJKTokenizer
All Implemented Interfaces:
Closeable

public final class CJKTokenizer
extends Tokenizer

CJKTokenizer is designed for Chinese, Japanese, and Korean languages.

The tokens returned are every two adjacent characters with overlap match.

Example: "java C1C2C3C4" will be segmented to: "java" "C1C2" "C2C3" "C3C4".

Additionally, the following is applied to Latin text (such as English): For more info on Asian language (Chinese, Japanese, and Korean) text segmentation: please search google


Nested Class Summary
 
Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource
AttributeSource.AttributeFactory, AttributeSource.State
 
Field Summary
 
Fields inherited from class org.apache.lucene.analysis.Tokenizer
input
 
Constructor Summary
CJKTokenizer(AttributeSource.AttributeFactory factory, Reader in)
           
CJKTokenizer(AttributeSource source, Reader in)
           
CJKTokenizer(Reader in)
          Construct a token stream processing the given input.
 
Method Summary
 void end()
          This method is called by the consumer after the last token has been consumed, after TokenStream.incrementToken() returned false (using the new TokenStream API).
 boolean incrementToken()
          Returns true for the next token in the stream, or false at EOS.
 void reset()
          Resets this stream to the beginning.
 void reset(Reader reader)
          Expert: Reset the tokenizer to a new reader.
 
Methods inherited from class org.apache.lucene.analysis.Tokenizer
close, correctOffset
 
Methods inherited from class org.apache.lucene.util.AttributeSource
addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, restoreState, toString
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 

Constructor Detail

CJKTokenizer

public CJKTokenizer(Reader in)
Construct a token stream processing the given input.

Parameters:
in - I/O reader

CJKTokenizer

public CJKTokenizer(AttributeSource source,
                    Reader in)

CJKTokenizer

public CJKTokenizer(AttributeSource.AttributeFactory factory,
                    Reader in)
Method Detail

incrementToken

public boolean incrementToken()
                       throws IOException
Returns true for the next token in the stream, or false at EOS. See http://java.sun.com/j2se/1.3/docs/api/java/lang/Character.UnicodeBlock.html for detail.

Specified by:
incrementToken in class TokenStream
Returns:
false for end of stream, true otherwise
Throws:
IOException - - throw IOException when read error
happened in the InputStream

end

public final void end()
Description copied from class: TokenStream
This method is called by the consumer after the last token has been consumed, after TokenStream.incrementToken() returned false (using the new TokenStream API). Streams implementing the old API should upgrade to use this feature.

This method can be used to perform any end-of-stream operations, such as setting the final offset of a stream. The final offset of a stream might differ from the offset of the last token eg in case one or more whitespaces followed after the last token, but a WhitespaceTokenizer was used.

Overrides:
end in class TokenStream

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. TokenStream.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 TokenStream.reset(). Note that if your TokenStream caches tokens and feeds them back again after a reset, it is imperative that you clone the tokens when you store them away (on the first pass) as well as when you return them (on future passes after TokenStream.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


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