private function generateName($key, $expiration = null) {

		if(null !== $expiration && false === ('-' . intval($expiration) == '-' . $expiration)) {
			return trigger_error(sprintf('Argument 2 passed to %s() must be of the type integer, "%s" given', __METHOD__, gettype($expiration)), E_USER_ERROR);
		}
		
		return md5(serialize($key)) . '-' . ($expiration ? $expiration : '*') . '-' . ($expiration ? (time() + $expiration) : '*') . Application :: get(['extensions', 'cache']);
	}