/**
  * The place to check if the data set in the snippet is valid
  * to generate the snippet.
  *
  * When invalid data should result in an error, you can throw it
  * here but you can also perform the check in the
  * checkRegistryRequestsAnswers() function from the
  * {@see \MUtil_Registry_TargetInterface}.
  *
  * @return boolean
  */
 public function hasHtmlOutput()
 {
     if (!($this->user->hasAllowedRole() && $this->user->canSetPassword())) {
         $this->addMessage($this->getNotAllowedMessage());
         return false;
     }
     return parent::hasHtmlOutput();
 }