code: private static String appendIfMissing(final String str, final CharSequence suffix, final boolean ignoreCase, final CharSequence... suffixes) {
          if (str == null || isEmpty(suffix) || endsWith(str, suffix, ignoreCase)) {
              return str;
          }
          if (suffixes != null && suffixes.length > 0) {
              for (final CharSequence s : suffixes) {
                  if (endsWith(str, s, ignoreCase)) {
                      return str;
                  }
              }
          }
          return str + suffix.toString();
      }
docs: Appends the suffix to the end of the string if the string does not
  already end with the suffix.
  
  @param str The string.
  @param suffix The suffix to append to the end of the string.
  @param ignoreCase Indicates whether the compare should ignore case.
  @param suffixes Additional suffixes that are valid terminators (optional).
  
  @return A new String if suffix was appended, the same string otherwise.