php - 领域驱动设计 - 聚合 - EventPublisher with Doctrine

Question

我想问一下在聚合中使用 EventPublisher。

class SomeAggregate
{

    private $eventPublisher;

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


}   

当我创建 SomeAggregate 时，我将 EventPublisher 传递给构造函数，一切正常。

但是当我从数据库中检索这个对象时呢？Doctrine 根据表中的字段重建对象，将跳过 EventPublisher。

如何让 Doctrine 每次从数据库中检索 SomeAggregate 时都注入(inject) EventPublisher？

如果存在的话，我的首选方法是将 $eventPublisher 属性映射到 EventPublisher 类。

Answer 1

使用 Doctrine 事件监听器。

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

在 AppBundle\EventListener\EventPublisherInjector 中:

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