protected function typeToClassName($typeName)
    {
        $classBase = Type::studlyCaps($typeName).'Type';

        $class = __NAMESPACE__."\\$classBase";

        if (class_exists($class)) {
            return $class;
        }

        $class = __NAMESPACE__."\UnitTypes\\$classBase";

        if (class_exists($class)) {
            return $class;
        }

        throw new ResourceNotFoundException("XType class for $typeName not found");
    }