public function connect()
    {
        $this->_service = new SplMemcached();
        $this->_service->addServer($this->_host, $this->_port);
        $stats = $this->_service->getStats();
        if (isset($stats[$this->_host.":".$this->_port])) {
            $this->_connected = true;
        } else {
            throw new ServiceException(
                "Unable to connect to Memcached service"
            );
        }

        return $this;
    }