org.apache.lucene.analysis
Class LowerCaseTokenizer

java.lang.Object
  org.apache.lucene.util.AttributeSource
      org.apache.lucene.analysis.TokenStream
          org.apache.lucene.analysis.Tokenizer
              org.apache.lucene.analysis.CharTokenizer
                  org.apache.lucene.analysis.LetterTokenizer
                      org.apache.lucene.analysis.LowerCaseTokenizer

public final class LowerCaseTokenizer
extends LetterTokenizer

LowerCaseTokenizer performs the function of LetterTokenizer and LowerCaseFilter together. It divides text at non-letters and converts them to lower case. While it is functionally equivalent to the combination of LetterTokenizer and LowerCaseFilter, there is a performance advantage to doing the two tasks at once, hence this (redundant) implementation.

Note: this does a decent job for most European languages, but does a terrible job for some Asian languages, where words are not separated by spaces.

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

LowerCaseTokenizer(AttributeSource.AttributeFactory factory, Reader in)
Construct a new LowerCaseTokenizer using a given AttributeSource.AttributeFactory.

LowerCaseTokenizer(AttributeSource source, Reader in)
Construct a new LowerCaseTokenizer using a given AttributeSource.

LowerCaseTokenizer(Reader in)
Construct a new LowerCaseTokenizer.

Method Summary

protected char

normalize(char c) Converts char to lower case Character.toLowerCase(char).

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

isTokenChar

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

end, incrementToken, next, next, reset

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

close, correctOffset

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

getOnlyUseNewAPI, reset, setOnlyUseNewAPI

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

LowerCaseTokenizer

public LowerCaseTokenizer(Reader in)

Construct a new LowerCaseTokenizer.

LowerCaseTokenizer

public LowerCaseTokenizer(AttributeSource source,
                          Reader in)

Construct a new LowerCaseTokenizer using a given AttributeSource.

LowerCaseTokenizer

public LowerCaseTokenizer(AttributeSource.AttributeFactory factory,
                          Reader in)

Construct a new LowerCaseTokenizer using a given AttributeSource.AttributeFactory.

Method Detail

normalize

protected char normalize(char c)

Converts char to lower case Character.toLowerCase(char).

Overrides:

normalize in class CharTokenizer