code: protected static char[] flags(final CharSequence... flagStrings) {
          final StringBuilder sb = new StringBuilder();
          for (CharSequence flags: flagStrings) sb.append(flags);
          return flags(sb.toString());
      }
docs: Converts strings of flags into a sorted flag array,
  that can be passed as a parameter to other utility methods.
  @param flagStrings
  @return sorted flag array