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From "Hiroaki Kawai (JIRA)" <j...@apache.org>
Subject [jira] Commented: (LUCENE-1216) CharDelimiterTokenizer
Date Thu, 15 May 2008 07:33:55 GMT

    [ https://issues.apache.org/jira/browse/LUCENE-1216?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12597036#action_12597036
] 

Hiroaki Kawai commented on LUCENE-1216:
---------------------------------------

The reason of setWhitespaceDelimiter():
Of cource we can call addDelimiter(' '), but it is usually insufficient.

Whitespace chars we think, is described as:
- It is a Unicode space character (SPACE_SEPARATOR, LINE_SEPARATOR, or PARAGRAPH_SEPARATOR)
 but is not also a non-breaking space ('\u00A0', '\u2007', '\u202F'). 
- It is '\u0009', HORIZONTAL TABULATION. 
- It is '\u000A', LINE FEED. 
- It is '\u000B', VERTICAL TABULATION. 
- It is '\u000C', FORM FEED. 
- It is '\u000D', CARRIAGE RETURN. 
- It is '\u001C', FILE SEPARATOR. 
- It is '\u001D', GROUP SEPARATOR. 
- It is '\u001E', RECORD SEPARATOR. 
- It is '\u001F', UNIT SEPARATOR. 
http://java.sun.com/javase/6/docs/api/java/lang/Character.html#isWhitespace(char)

I thought the white space chars are so many that it is hard to register each time. 

> CharDelimiterTokenizer
> ----------------------
>
>                 Key: LUCENE-1216
>                 URL: https://issues.apache.org/jira/browse/LUCENE-1216
>             Project: Lucene - Java
>          Issue Type: Improvement
>          Components: Analysis
>            Reporter: Hiroaki Kawai
>            Assignee: Otis Gospodnetic
>            Priority: Minor
>         Attachments: CharDelimiterTokenizer.java, CharDelimiterTokenizer.java, TestCharDelimiterTokenizer.java
>
>
> WhitespaceTokenizer is very useful for space separated languages, but my Japanese text
is not always separated by a space. So, I created an alternative Tokenizer that we can specify
the delimiter. The file submitted will be an improvement of the current WhitespaceTokenizer.
> I tried to extend it from CharTokenizer, but CharTokenizer has a limitation that a token
can't be longer than 255 chars.

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