public function save($id, $data, $lifetime = null, $tag = null)
    {
        try {
            if (\apc_store($id, $data, $lifetime)) {
                $this->_hashmap[$tag][$id] = array("time" => time(), "ttl" => $lifetime);

                return $this->saveHashmap();
            } else {
                return false;
            }
        } catch (\Exception $e) {
            $this->log('warning', \sprintf('Unable to save cache for id %s : %s', $id, $e->getMessage()));

            return false;
        }

        return true;
    }