[SoftDeleteable] Use ListenersInvoker instead of EventManager

[raymondschouten]

Feature Request

This is a follow up for closed issues #1285, #1286 and #2136.

Currently the SoftDeleteable events are dispatched using the Doctrine EventManager, however that is only one of the three ways how you can subscribe to events in Doctrine ORM. You can also subscribe to events via lifecycle callbacks and entity listeners. All 3 "systems" are covered by Doctrine when using the ListenersInvoker.

My use-case right now, is that I have entity listeners (not to be confused with event listeners), which make it possible to listen to events targeted to specific entities. This eliminates the need to dispatch the entire event if nobody is listening, and it eliminates the need to do an instanceof check, to see if it is about the entity I expect. However, since the SoftDeleteable events use the EventManager, my entity listeners will not be executed for these events.

It is quite simple to use the ListenersInvoker, just replace (pseudo-code):

$eventManager = $entityManager->getEventManager();
$eventManager->dispatchEvent(self::PRE_SOFT_DELETE, new LifecycleEventArgs($entity, $entityManager));

with:

$classMetadata = $entityManager->getClassMetadata(get_class($entity));
$listenersInvoker = new ListenersInvoker($entityManager);

$invoke = $listenersInvoker->getSubscribedSystems($classMetadata, self::PRE_SOFT_DELETE);

if ($invoke !== ListenersInvoker::INVOKE_NONE) {
    $listenersInvoker->invoke($classMetadata, self::PRE_SOFT_DELETE, $entity, new LifecycleEventArgs($entity, $entityManager), $invoke);
}