public override TokenStream TokenStream(string fieldName, TextReader reader)
        {
            var attributeSource = new AttributeSource();

            attributeSource.AddAttributeImpl(new SpellAttribute());
            attributeSource.AddAttributeImpl(new StemAttribute());

            var tokenizer       = new RussianLetterTokenizer(attributeSource, reader);
            var lowercaseFilter = new LowerCaseFilter(tokenizer);
            var badWordsFilter  = new BadWordsFilter(lowercaseFilter);
            var stopWordFilter  = new StopFilter(false, badWordsFilter, StopWords);
            var preFilter       = new StemFilter(stopWordFilter, SpellChecker, NumberOfSuggestions);
            var similarFilter   = new SimilarFilter(preFilter);

            return(similarFilter);
        }