I give all the credits to Richard for pointing me into the right direction, so I’m accepting his answer. Nevertheless I also publish my answer with the complete code for future visitors.
class ProjectEntitySubscriber implements EventSubscriber
{
public function getSubscribedEvents()
{
return array(
'onFlush',
);
}
public function onFlush(OnFlushEventArgs $args)
{
$em = $args->getEntityManager();
$uow = $em->getUnitOfWork();
foreach ($uow->getScheduledEntityUpdates() as $keyEntity => $entity) {
if ($entity instanceof ProjectTolerances) {
foreach ($uow->getEntityChangeSet($entity) as $keyField => $field) {
$notification = new ProjectNotification();
// place here all the setters
$em->persist($notification);
$classMetadata = $em->getClassMetadata('AppBundle\Entity\ProjectNotification');
$uow->computeChangeSet($classMetadata, $notification);
}
}
}
}
}