code: public final void validate() throws ValidationException {
  
          /*
           * ; the following are optional, ; but MUST NOT occur more than once (";" "VALUE" "=" ("DATE-TIME" / "DATE")) /
           * (";" tzidparam) /
           */
          ParameterValidator.getInstance().assertOneOrLess(Parameter.VALUE,
                  getParameters());
  
          final Parameter valueParam = getParameter(Parameter.VALUE);
  
          if (valueParam != null && !Value.DATE_TIME.equals(valueParam)
                  && !Value.DATE.equals(valueParam)) {
              throw new ValidationException("Parameter [" + Parameter.VALUE
                      + "] is invalid");
          }
  
          ParameterValidator.getInstance().assertOneOrLess(Parameter.TZID,
                  getParameters());
  
          /*
           * ; the following is optional, ; and MAY occur more than once (";" xparam)
           */
      }
docs: {@inheritDoc}