code: @Nonnull
    @ReturnsMutableObject ("design")
    private static byte [] _getAlphabet (final int options)
    {
      if ((options & URL_SAFE) == URL_SAFE)
        return _URL_SAFE_ALPHABET;
      if ((options & ORDERED) == ORDERED)
        return _ORDERED_ALPHABET;
      return _STANDARD_ALPHABET;
    }
docs: Returns one of the _SOMETHING_ALPHABET byte arrays depending on the options
  specified. It's possible, though silly, to specify ORDERED <b>and</b>
  URLSAFE in which case one of them will be picked, though there is no
  guarantee as to which one will be picked.