public function enableCache ( $options = null )
    {
        $key = isset($options["key"]) ? $options["key"] : "";
        $lifetime = isset($options["lifetime"]) ? $options["lifetime"] : 3600;
        $level = isset($options["level"]) ? $options["level"] : 1;
        $this->_cache_service_name = isset($options["service"]) ? $options["service"] : "cache";

        $view_level_name = $this->_getViewLevelNameFromLevel( $level );

        $this->_view_levels[$view_level_name]["cache_enabled"] = array(
            "key" => $key,
            "lifetime" => $lifetime
        );
    }