org.apache.lucene.analysis
Class LowerCaseTokenizer

java.lang.Object
  |
  +--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.

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

input

Constructor Summary

LowerCaseTokenizer(Reader in)
Construct a new LowerCaseTokenizer.

Method Summary

protected char

normalize(char c) Collects only characters which satisfy Character#isLetter(char).

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

isTokenChar

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

next

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

close

Methods inherited from class java.lang.Object

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

Constructor Detail

LowerCaseTokenizer

public LowerCaseTokenizer(Reader in)

Construct a new LowerCaseTokenizer.

Method Detail

normalize

protected char normalize(char c)

Collects only characters which satisfy Character#isLetter(char).

Overrides:

normalize in class CharTokenizer