gistfile1.php

<?php

namespace Project\BackendBundle\EventListener;
//src/Project/BackendBundle/EventListener/ClippedImagesManager.php

use Doctrine\ORM\Event\LifecycleEventArgs;
use Doctrine\ORM\Event\PostFlushEventArgs;
use Project\BackendBundle\Entity\Subitem;

class ClippedImagesManager 
{

  public function preUpdate(LifecycleEventArgs $args)
  {
    die("jklfs");
  }

//src/Project/BackendBundle/Resources/config/services.yml
services:
  project.clipped_images_manager:
      class: Project\BackendBundle\EventListener\ClippedImagesManager
      tags:
          - { name: doctrine.event_listener, event: preUpdate }