/**
  * Add input elements to definition form
  *
  * @param ilPropertyFormGUI $a_form
  * @param ilAdvancedMDPermissionHelper $a_form
  */
 public function addToFieldDefinitionForm(ilPropertyFormGUI $a_form, ilAdvancedMDPermissionHelper $a_permissions)
 {
     global $lng;
     $perm = $a_permissions->hasPermissions(ilAdvancedMDPermissionHelper::CONTEXT_FIELD, $this->getFieldId(), array(array(ilAdvancedMDPermissionHelper::ACTION_FIELD_EDIT_PROPERTY, ilAdvancedMDPermissionHelper::SUBACTION_FIELD_TITLE), array(ilAdvancedMDPermissionHelper::ACTION_FIELD_EDIT_PROPERTY, ilAdvancedMDPermissionHelper::SUBACTION_FIELD_DESCRIPTION), array(ilAdvancedMDPermissionHelper::ACTION_FIELD_EDIT_PROPERTY, ilAdvancedMDPermissionHelper::SUBACTION_FIELD_SEARCHABLE), array(ilAdvancedMDPermissionHelper::ACTION_FIELD_EDIT_PROPERTY, ilAdvancedMDPermissionHelper::SUBACTION_FIELD_PROPERTIES)));
     // title
     $title = new ilTextInputGUI($lng->txt('title'), 'title');
     $title->setValue($this->getTitle());
     $title->setSize(20);
     $title->setMaxLength(70);
     $title->setRequired(true);
     $a_form->addItem($title);
     if (!$perm[ilAdvancedMDPermissionHelper::ACTION_FIELD_EDIT_PROPERTY][ilAdvancedMDPermissionHelper::SUBACTION_FIELD_TITLE]) {
         $title->setDisabled(true);
     }
     // desc
     $desc = new ilTextAreaInputGUI($lng->txt('description'), 'description');
     $desc->setValue($this->getDescription());
     $desc->setRows(3);
     $desc->setCols(50);
     $a_form->addItem($desc);
     if (!$perm[ilAdvancedMDPermissionHelper::ACTION_FIELD_EDIT_PROPERTY][ilAdvancedMDPermissionHelper::SUBACTION_FIELD_DESCRIPTION]) {
         $desc->setDisabled(true);
     }
     // searchable
     $check = new ilCheckboxInputGUI($lng->txt('md_adv_searchable'), 'searchable');
     $check->setChecked($this->isSearchable());
     $check->setValue(1);
     $a_form->addItem($check);
     if (!$perm[ilAdvancedMDPermissionHelper::ACTION_FIELD_EDIT_PROPERTY][ilAdvancedMDPermissionHelper::SUBACTION_FIELD_SEARCHABLE]) {
         $check->setDisabled(true);
     }
     /* required
     		$check = new ilCheckboxInputGUI($lng->txt('md_adv_required'), 'required');
     		$check->setChecked($this->isRequired());
     		$check->setValue(1);
     		$a_form->addItem($check);		 
     		*/
     $this->addCustomFieldToDefinitionForm($a_form, !$perm[ilAdvancedMDPermissionHelper::ACTION_FIELD_EDIT_PROPERTY][ilAdvancedMDPermissionHelper::SUBACTION_FIELD_PROPERTIES]);
 }