protected function get_display_category_url(Category $category)
 {
     switch ($category->get_type()) {
         case ForumCategory::TYPE_URL:
             $url = new Url($category->get_url());
             break;
         case ForumCategory::TYPE_FORUM:
             $url = ForumUrlBuilder::display_forum($category->get_id(), $category->get_rewrited_name());
             break;
         default:
             $url = ForumUrlBuilder::display_category($category->get_id(), $category->get_rewrited_name());
             break;
     }
     return $url;
 }