public function set($key, $value, $lifeTime)
    {

        $path = $this->getKeyPath($key);
        $dir = dirname($path);

        if (!is_dir($dir))
            mkdir($dir, 0777, true);

        $this->_lifeTimes[$key] = intval($lifeTime);

        //Save the life times
        $this->_format->save($this->_lifeTimePath, $this->_lifeTimes);

        //Save the cache content
        $this->_format->save($path, $value);

        return $this;
    }