code: public final void validate() throws ValidationException {
  
          /*
           * ; the following is optional, ; but MUST NOT occur more than once (";" fbtypeparam) /
           */
          ParameterValidator.getInstance().assertOneOrLess(Parameter.FBTYPE,
                  getParameters());
  
          /*
           * ; the following is optional, ; and MAY occur more than once (";" xparam)
           */
  
          if (!periods.isUtc()) {
              throw new ValidationException("Periods must be in UTC format");
          }
      }
docs: {@inheritDoc}