Doctrine2 Event Listeners? Subscribers? Dispatching? - doctrine-orm

Question

I've read the documentation several times but I am missing something.. I can't seem to make this work.
Scenario: I have an entity of Tshirts (id,qtyTotals) and an entity of Sizes (tshirt_id, size, qty) and every time a new Size is created,updated or deleted, I need to update the Tshirts.qtyTotals by selecting all the Sizes, adding them up and updating the totals.
I am sure I could do this from my controller in 2 separate steps, but I feel the Events approach is the right one.
I've been reading this http://docs.doctrine-project.org/projects/doctrine-orm/en/latest/reference/events.html#entity-listeners specially the 2.4 sections.
I was trying to use the annotation: #ORM\EntityListeners({"TshirtListener"}) but the class is found but never execute it....
How do I define the events? how do I dispatch them? What is the difference between a Listener and a Subscriber?
A simple example would be greatly appreciated.
Thank you.

Answer 1

You can attach events to an Entity using the Doctrine Event Manager in the module Module.php class in the onBootstrap function like the following:
class Module
{
public function onBootstrap(MvcEvent $e)
{
$application = $e->getApplication();
$sm = $application->getServiceManager();
$doctrineEntityManager = $sm->get('doctrine.entitymanager.orm_default');
$doctrineEventManager = $doctrineEntityManager->getEventManager();
$doctrineEventManager->addEventListener(
array(\Doctrine\ORM\Events::prePersist, \Doctrine\ORM\Events::preUpdate),
new \Application\Listener\MyEntityListener($sm)
);
}
}
And in the Listener you can do what ever you want like this for example:
namespace Application\Listener;
class EntityListener
{
private $sm;
public function __construct($sm)
{
$this->sm = $sm;
}
public function prePersist($eventArgs)
{
$entity = $eventArgs->getEntity();
if (method_exists($entity, 'setTotals')) {
//Update entity totals
}
}
public function preUpdate($eventArgs)
{
$entity = $eventArgs->getEntity();
if (method_exists($entity, 'setTotals')) {
//Update entity totals
}
}
}