code: private String findSuffixPartByKey(String key) {
      for (String part : splitSuffix(request.getRequestPathInfo().getSuffix())) {
        if (part.indexOf(KEY_VALUE_DELIMITER) >= 0) {
          String partKey = decodeKey(part);
          if (partKey.equals(key)) {
            String value = decodeValue(part);
            return value;
          }
        }
      }
      return null;
    }
docs: Extract the value of a named suffix part from this request's suffix
  @param key key of the suffix part
  @return the value of that named parameter (or null if not used)