/**
  * @see	\wcf\form\IForm::validate()
  */
 public function validate()
 {
     parent::validate();
     if (empty($this->server)) {
         throw new UserInputException('server');
     }
     if (!PackageUpdateServer::isValidServerURL($this->server)) {
         throw new UserInputException('server', 'notValid');
     }
 }