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From Ahmed Al-Obaidy <>
Subject Re: Arabic Analyzer: possible bug
Date Thu, 08 Oct 2009 13:18:56 GMT
There is no upper and lower case in Arabic.

--- On Thu, 10/8/09, DM Smith <> wrote:

From: DM Smith <>
Subject: Re: Arabic Analyzer: possible bug
Date: Thursday, October 8, 2009, 3:14 PM

Robert,Thanks for the info.As I said, I am illiterate in Arabic. So I have another, perhaps
nonsensical, question:Does the stop word list have every combination of upper/lower case for
each Arabic word in the list? (i.e. is it fully de-normalized?) Or should it come after LowerCaseFilter?
-- DM
On Oct 8, 2009, at 8:37 AM, Robert Muir wrote:
DM, this isn't a bug.

The arabic stopwords are not normalized.

but for persian, i normalized the stopwords. mostly because i did not want to have to create
variations with farsi yah versus arabic yah for each one.

On Thu, Oct 8, 2009 at 7:24 AM, DM Smith <> wrote:

I'm wondering if there is  a bug in ArabicAnalyzer in 2.9. (I don't know Arabic or Farsi,
but have some texts to index in those languages.)
The tokenizer/filter chain for ArabicAnalyzer is:

        TokenStream result = new ArabicLetterTokenizer( reader );
        result = new StopFilter( result, stoptable );
        result = new LowerCaseFilter(result);
        result = new ArabicNormalizationFilter( result );

        result = new ArabicStemFilter( result );

        return result;

Shouldn't the StopFilter come after ArabicNormalizationFilter?

 As a comparison the PersianAnalyzer has:

    TokenStream result = new ArabicLetterTokenizer(reader);
    result = new LowerCaseFilter(result);
    result = new ArabicNormalizationFilter(result);

    /* additional persian-specific normalization */
    result = new PersianNormalizationFilter(result);
     * the order here is important: the stopword list is normalized with the
     * above!

    result = new StopFilter(result, stoptable);

    return result;



Robert Muir

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