use Symfony\Component\Config\Definition\ConfigurationInterface;
use Symfony\Component\DependencyInjection\Extension\ExtensionInterface;

class Kernel extends BaseKernel implements ExtensionInterface, ConfigurationInterface
{
       public function load(array $configs, ContainerBuilder $container)
	{
		$processor = new Processor();
		$config    = $processor->processConfiguration($this, $configs);
	}

	public function getNamespace()
	{
		return '';
	}

	public function getXsdValidationBasePath()
	{
		return false;
	}

	public function getAlias()
	{
		return 'foobar';
	}

	public function getConfigTreeBuilder()
	{
		$tree = new TreeBuilder($this->getAlias());
                // do something
                return $tree;
        }
}