在实体中创建一个方法，在调用它时进行延迟加载

I work with Redis loaded as a service to inject followers to a entity. So i've a entity like User that has a method like getFollowers. I don't want to mix service with entities, so I make a listener that subscribe to postLoad events in Doctrine.

The question is how call the service only when I call the getFollowers method.

My code...

EventListener:

public function postLoad(LifecycleEventArgs $eventArgs)
{

    $redisService = get the service loaded with DIC in constructor. 

    if ($eventArgs->getEntity() instanceof User) {
        $user = $eventArgs->getEntity();

        $user->setFollowers($redisService->getFollowers($user));

    }

}

User entity:

public function setFollowers(Array $followers) {
    $this->followers = $followers
}

My problem is that on every load of class user, the RedisService is called and loaded, and I'd like to call the service ONLY on $user->getFollowers

Finally I get the answer...

In my listener postLoad I assign a closure to property of object:

$socialGraph = $this->socialGraph;
$getFollowers = function() use ($socialGraph, $user) {
    return $socialGraph->getFollowers($user->getId());
};

$user->setFans($getFollowers);

Now, in my object it's possible to call a method into a property with:

public function getFans()
{
    return call_user_func($this->fans);

 // another way
    return $this->fans->__invoke();
}

Wrap it as singleton. Something like that?

if (is_callable($this->_lazyLoad)) {
    $this->_lazyLoad = $this->_lazyLoad($this);
}

return $this->_lazyLoad;