protected function createController($controller)
    {
        if (false === strpos($controller, '::')) {
            $count = substr_count($controller, ':');
            if (2 == $count && $this->parser) {
                // controller in the a:b:c notation then
                $controller = $this->parser->parse($controller);
            }
            else if (1 == $count) {
                // controller in the service:method notation
                list($service, $method) = explode(':', $controller, 2);
                return array($this->container->get($service), $method);
            }
            else if ($this->container->has($controller) && method_exists($service = $this->container->get($controller), '__invoke')) {
                return $service;
            }
            else {
                throw new \InvalidArgumentException(sprintf('Unable to find controller "%s".', $controller));
            }
        }

        list($class, $method) = explode('::', $controller, 2);

        if (!class_exists($class)) {
            throw new \InvalidArgumentException(sprintf('Class "%s" does not exist.', $class));
        }

        $controller = $this->instantiateController($class);

        return array($controller, $method);
    }