public function getBundlePrefix(AbstractResourceBundle $bundle = null)
    {
        if (is_null($bundle)) {
            $bundle = $this->bundle;
        }

        $containerExtension = new \ReflectionClass($bundle->getContainerExtension());
        $applicationName = $containerExtension->getProperty('applicationName');
        $applicationName->setAccessible(true);
        $extension = $bundle->getContainerExtension();

        return $applicationName->getValue(new $extension());
    }