protected function getClassProperties()
    {
        $properties = parent::getClassProperties();
        unset($properties[taoItems_models_classes_ItemsService::PROPERTY_ITEM_MODEL]);
        unset($properties[taoItems_models_classes_ItemsService::PROPERTY_ITEM_CONTENT]);
        unset($properties[taoItems_models_classes_ItemsService::PROPERTY_ITEM_CONTENT_SRC]);
        return $properties;
    }