Symfony2 soft delete

services.yml

services:
    task.subscriber:
        class: Arcanys\TrainingBundle\EventListener\TaskEventListener
        tags:
            - { name: doctrine.event_subscriber, connection: default }

TaskEventListener.php

<?php namespace Arcanys\TrainingBundle\EventListener;

use Doctrine\Common\EventSubscriber;
use Doctrine\ORM\Event\LifecycleEventArgs;
use Doctrine\ORM\Events;
use Arcanys\TrainingBundle\Entity\Task;

class TaskEventListener implements EventSubscriber{

    public function getSubscribedEvents()
    {
        return array(
            Events::preRemove,
        );
    }


    public function preRemove(LifecycleEventArgs $args)
    {
    	 $entity = $args->getEntity();
    	if ($entity instanceof Task) {


	       
	        $em = $args->getEntityManager();


			$entity->setDeleted(true);
			$em->detach($entity);
			
			$entity->setDeleted(true);
			$em->merge($entity);
			
    	}
    }
}