Symfony\Component\DependencyInjection\DefinitionDecorator::setClass PHP Method

    public function setClass($class)
    {
        $this->changes['class'] = true;

        return parent::setClass($class);
    }

 public function process(ContainerBuilder $container)
 {
     if (!($container->hasDefinition('fragment.listener') && $container->hasDefinition('ezpublish.decorated_fragment_renderer'))) {
         return null;
     }
     $fragmentListenerDef = $container->findDefinition('fragment.listener');
     $fragmentListenerDef->setFactoryService('ezpublish.fragment_listener.factory')->setFactoryMethod('buildFragmentListener')->addArgument('%fragment.listener.class%');
     // Looping over all fragment renderers to decorate them
     // This is to make sure they are siteaccess aware (siteaccess is serialized in rendered path).
     foreach ($container->findTaggedServiceIds('kernel.fragment_renderer') as $id => $attributes) {
         $renamedId = "{$id}.inner";
         $definition = $container->getDefinition($id);
         $public = $definition->isPublic();
         $tags = $definition->getTags();
         $definition->setPublic(false);
         $container->setDefinition($renamedId, $definition);
         $decoratedDef = new DefinitionDecorator('ezpublish.decorated_fragment_renderer');
         $decoratedDef->setArguments(array(new Reference($renamedId)));
         $decoratedDef->setPublic($public);
         $decoratedDef->setTags($tags);
         // Special treatment for inline fragment renderer, to fit ESI renderer constructor type hinting (forced to InlineFragmentRenderer)
         if ($id === 'fragment.renderer.inline') {
             $decoratedDef->setClass($container->getParameter('ezpublish.decorated_fragment_renderer.inline.class'));
         }
         $container->setDefinition($id, $decoratedDef);
     }
 }