private function loadResourceMetadata()
    {
        foreach (get_declared_classes() as $className) {
            if (
                !isset($this->resources[$className]) &&
                is_subclass_of($className, 'Tonic\Resource')
            ) {
                $rm = new ResourceMetadata($className);
                if ($rm->getUri()) {
                    $this->resources[$className] = $rm;
                }
            }
        }
    }