public function setCache() {
        if (!file_exists($this->_fileName)) {
            file_put_contents($this->_fileName, $this->_compress(serialize($this->_content)));
        }

        $timeAgo = time() - filemtime($this->_fileName);

        if ($timeAgo > $this->_time) {
            file_put_contents($this->_fileName, $this->_compress(serialize($this->_content)));
        }
    }