public function checkInput()
 {
     if ($this->getRequired() && !isset($_POST[$this->getPostVar()])) {
         global $lng;
         $this->setAlert($lng->txt("msg_input_is_required"));
         return false;
     }
     return parent::checkInput();
 }
 /**
  * Allows to add additional form fields to the certificate editor form
  * This method will be called when the certificate editor form will built
  * using the ilPropertyFormGUI class. Additional fields will be added at the
  * bottom of the form.
  *
  * @param object $form An ilPropertyFormGUI instance
  * @param array $form_fields An array containing the form values. The array keys are the names of the form fields
  */
 public function addAdditionalFormElements(&$form, $form_fields)
 {
     global $lng;
     $short_name = new ilTextInputGUI($lng->txt("certificate_short_name"), "short_name");
     $short_name->setRequired(TRUE);
     require_once "./Services/Utilities/classes/class.ilStr.php";
     $short_name->setValue(strlen($form_fields["short_name"]) ? $form_fields["short_name"] : ilStr::subStr($this->object->getTitle(), 0, 30));
     $short_name->setSize(30);
     if (strlen($form_fields["short_name"])) {
         $short_name->setInfo(str_replace("[SHORT_TITLE]", $form_fields["short_name"], $lng->txt("certificate_short_name_description")));
     } else {
         $short_name->setInfo($lng->txt("certificate_short_name_description"));
     }
     if (count($_POST)) {
         $short_name->checkInput();
     }
     $form->addItem($short_name);
     $visibility = new ilCheckboxInputGUI($lng->txt("certificate_enabled_scorm"), "certificate_enabled_scorm");
     $visibility->setInfo($lng->txt("certificate_enabled_scorm_introduction"));
     $visibility->setValue(1);
     if ($form_fields["certificate_enabled_scorm"]) {
         $visibility->setChecked(TRUE);
     }
     if (count($_POST)) {
         $visibility->checkInput();
     }
     $form->addItem($visibility);
 }