public KuromojiTokenizerFactory(IndexSettings indexSettings, Environment env, String name, Settings settings) {
        super(indexSettings, settings, name);
        mode = getMode(settings);
        userDictionary = getUserDictionary(env, settings);
        discartPunctuation = settings.getAsBoolean("discard_punctuation", true);
        nBestCost = settings.getAsInt(NBEST_COST, -1);
        nBestExamples = settings.get(NBEST_EXAMPLES);
    }