protected function validateOne()
 {
     setContentType("json");
     $group = new Group();
     $given = array_keys($_POST);
     $response["error"] = null;
     if (count($given) == 1) {
         if ($given[0] == "name") {
             $group->setName($_POST["name"]);
             $g = GroupQuery::create()->filterByOwner($this->data["loggedUser"])->filterByName($_POST["name"])->findOne();
             if ($g) {
                 $response["error"] = array("name" => "name", "message" => "You can not have two groups with the same name.");
                 $this->viewString(json_encode($response));
                 return;
             }
         } else {
             if ($given[0] == "description") {
                 $group->setDescription($_POST["description"]);
             } else {
                 setHTTPStatusCode("400");
                 return;
             }
         }
         if (!$group->validate()) {
             foreach ($group->getValidationFailures() as $failure) {
                 if ($given[0] == $failure->getPropertyPath()) {
                     $response["error"] = array("name" => $failure->getPropertyPath(), "message" => $failure->getMessage());
                 }
             }
         }
         $this->viewString(json_encode($response));
     } else {
         setHTTPStatusCode("400");
     }
 }