'ヒ', 'フ', 'ヘ', 'ホ', 'マ', 'ミ', 'ム', 'メ', 'モ', 'ヤ', 'ユ', 'ヨ', 'ラ', 'リ', 'ル', 'レ', 'ロ', 'ワ', 'ン', '゛', '゜' };

    private static final char HANKAKU_KATAKANA_FIRST_CHAR = HANKAKU_KATAKANA[0];

    private static final char HANKAKU_KATAKANA_LAST_CHAR = HANKAKU_KATAKANA[HANKAKU_KATAKANA.length - 1];

    @Override
    public String normalize(final String s, final String field, final String... langs) {
        if (s.length() == 0) {