/**
  * This method will ensure that all runtime parameters marked 'required' have been specified.
  * Otherwise, a ParameterValueException will be thrown.
  *
  * @throws ParameterValueException if a required parameter is missing
  */
 public void ensureRequiredParametersArePresent() throws ParameterValueException {
   for (ApplicationParameter param : _parameters.values()) {
     if (param.isRequired() && !param.isPresent())
       throw new ParameterValueException(
           param, null, "Required parameter " + param.getName() + " not set.");
   }
 }