Vietnamese diacritics

VietnameseDiacritics.java

public class VietnameseDiacritics {

  // this is only pseudo code, not meant to compile

    public static String allVietnameseCombiningDiacriticalMarks() {
        String s = "ạàáãảâăư"; // đ is not counted as a diacratic apparently
        s = java.text.Normalizer.normalize(s, java.text.Normalizer.Form.NFD);
        s = s.replaceAll("[^\\p{InCombiningDiacriticalMarks}]", "");
        return s;
    }

    private String removeNonVietnameseDiacritics(String input) {
        input = java.text.Normalizer.normalize(input, java.text.Normalizer.Form.NFD);
        input = input.replaceAll("[\\p{InCombiningDiacriticalMarks}&&[^" + VIETNAMESE_DIACRITICS + "]]", "");
        input = java.text.Normalizer.normalize(input, java.text.Normalizer.Form.NFKC);
        return input;
    }
}