extra.put("kanji_number", KanjiNumberFilterFactory::new);
        extra.put("kuromoji_pos_concat", PosConcatenationFilterFactory::new);
        extra.put("char_type", CharTypeFilterFactory::new);
        extra.put("number_concat", NumberConcatenationFilterFactory::new);
        extra.put("pattern_concat", PatternConcatenationFilterFactory::new);
        extra.put("stop_prefix", StopTokenPrefixFilterFactory::new);