public function acquire_lock($key) {
        $key = $this->parse_key($key);
        if ($this->nativelocking) {
            return $this->get_store()->acquire_lock($key, $this->get_identifier());
        } else {
            $this->ensure_cachelock_available();
            return $this->cachelockinstance->lock($key, $this->get_identifier());
        }
    }