public function __construct($pModel)
 {
     parent::__construct($pModel);
     if ($this->mModel instanceof SimpleModel) {
         throw new Exception("model of foreign model can't be a simple model");
     }
 }
 /**
  * don't instanciate a model by yourself because it take time
  * to get a model instance use singleton InstanceModel
  */
 public function __construct($pModel, $pElementName)
 {
     parent::__construct($pModel);
     $this->mElementName = $pElementName;
 }