域驱动设计 - 聚合 - 带有Doctrine的EventPublisher

Question

I would like to ask about using EventPublisher inside aggregate.

class SomeAggregate
{

    private $eventPublisher;

    public function __construct(EventPublisher $eventPublisher)
    {
        $this->eventPublisher = $eventPublisher;
    }


}   

When I create SomeAggregate I pass EventPublisher to the constructor and everything goes fine.

But what about when I retrieve this object from database. Doctrine makes reconstruction of the object based on the fields from table and will skip EventPublisher.

How to make Doctrine inject EventPublisher every time it retrieves SomeAggregate from database?

My prefered way, if such exists, is to map $eventPublisher property to EventPublisher class.

Answer 1

With a Doctrine Event Listener.

services:
    my.listener:
        class: AppBundle\EventListener\EventPublisherInjector
        arguments: [@event_publisher_service_id]
        tags:
            - { name: doctrine.event_listener, event: postLoad }

In AppBundle\EventListener\EventPublisherInjector:

public function __construct(EventPublisher $eventPublisher)
{
    $this->eventPublisher = $eventPublisher;
}

public function postLoad(LifecycleEventArgs $args)
{
    $entity = $args->getEntity();
    if ($entity instanceof SomeAggregate) {
         $entity->setEventPublisher($this->eventPublisher);
    }
} 

http://symfony.com/doc/current/cookbook/doctrine/event_listeners_subscribers.html

http://doctrine-orm.readthedocs.org/en/latest/reference/events.html#postload