public override TokenStream TokenStream(string fieldName, TextReader reader)
{
TokenStream result = new ArabicLetterTokenizer(reader);
result = new LowerCaseFilter(result);
// the order here is important: the stopword list is not normalized!
result = new StopFilter(StopFilter.GetEnablePositionIncrementsVersionDefault(matchVersion), result, stoptable);
result = new ArabicNormalizationFilter(result);
result = new ArabicStemFilter(result);
return result;
}