@Override
    public TokenStream create(TokenStream tokenStream) {
        return new AlphaFilter(tokenStream);
    }
Factory for filter that only allows tokens with characters that "isAlphabetic"  or "isIdeographic" through.
tika-eval/tika-eval-core/src/main/java/org/apache/tika/eval/core/tokens/AlphaIdeographFilterFactory.java