code: private void appendAffix(StringBuffer buffer, String affix, boolean localized) {
          boolean needQuote;
          if (localized) {
              needQuote = affix.indexOf(symbols.getZeroDigit()) >= 0
                  || affix.indexOf(symbols.getGroupingSeparator()) >= 0
                  || affix.indexOf(symbols.getDecimalSeparator()) >= 0
                  || affix.indexOf(symbols.getPercent()) >= 0
                  || affix.indexOf(symbols.getPerMill()) >= 0
                  || affix.indexOf(symbols.getDigit()) >= 0
                  || affix.indexOf(symbols.getPatternSeparator()) >= 0
                  || affix.indexOf(symbols.getMinusSign()) >= 0
                  || affix.indexOf(CURRENCY_SIGN) >= 0;
          } else {
              needQuote = affix.indexOf(PATTERN_ZERO_DIGIT) >= 0
                  || affix.indexOf(PATTERN_GROUPING_SEPARATOR) >= 0
                  || affix.indexOf(PATTERN_DECIMAL_SEPARATOR) >= 0
                  || affix.indexOf(PATTERN_PERCENT) >= 0
                  || affix.indexOf(PATTERN_PER_MILLE) >= 0
                  || affix.indexOf(PATTERN_DIGIT) >= 0
                  || affix.indexOf(PATTERN_SEPARATOR) >= 0
                  || affix.indexOf(PATTERN_MINUS) >= 0
                  || affix.indexOf(CURRENCY_SIGN) >= 0;
          }
          if (needQuote) buffer.append('\'');
          if (affix.indexOf('\'') < 0) buffer.append(affix);
          else {
              for (int j=0; j<affix.length(); ++j) {
                  char c = affix.charAt(j);
                  buffer.append(c);
                  if (c == '\'') buffer.append(c);
              }
          }
          if (needQuote) buffer.append('\'');
      }
docs: Append an affix to the given StringBuffer, using quotes if
  there are special characters.  Single quotes themselves must be
  escaped in either case.