public static function routeExists($identifier, $domain = null) {

    	if(false === is_string($identifier)) {
    		return trigger_error(sprintf('Argument 1 passed to %s() must be of the type string, "%s" given', __METHOD__, gettype($identifier)), E_USER_ERROR);
    	}

    	if(null !== $domain && false === is_string($domain)) {
    		return trigger_error(sprintf('Argument 2 passed to %s() must be of the type string, "%s" given', __METHOD__, gettype($domain)), E_USER_ERROR);
    	}

    	$routes = static :: getRoutes();

    	if(false === isset($routes[$identifier])) {
    		return false;
    	}

    	if(null !== $domain) {
    		return static :: domainExists($domain);
    	}

    	return true;
    }