Akka: Spring Integration

Shitty Author — Wed, 26 Aug 2015 18:07:53 +0000

PROBLEM

To create Spring-managed prototype-scoped actors.

SOLUTION

The key to this solution is to create a custom implementation of IndirectActorProducer. From the documentation:-

“…This interface defines a class of actor creation strategies deviating from the usual default of just reflectively instantiating the Actor subclass. It can be used to allow a dependency injection framework to determine the actual actor class and how it shall be instantiated…”

First, create an implementation of IndirectActorProducer that creates the actor using Spring’s ApplicationContext.

public final class SpringActorProducer implements IndirectActorProducer {
    private final ApplicationContext applicationContext;
    private final Class actorClass;

    public SpringActorProducer(final ApplicationContext applicationContext,
                               final Class actorClass) {
        this.applicationContext = applicationContext;
        this.actorClass = actorClass;
    }

    @Override
    public Actor produce() {
        return applicationContext.getBean(actorClass);
    }

    @Override
    public Class actorClass() {
        return actorClass;
    }
}

To prevent tedious auto-wiring ApplicationContext in every actor class to be passed to SpringActorProducer above, create a Spring-managed service that will do just that.

@Component
public final class SpringProps {
    private final ApplicationContext applicationContext;

    @Autowired
    public SpringProps(final ApplicationContext applicationContext) {
        this.applicationContext = applicationContext;
    }

    public Props create(final Class actorClass) {
        return Props.create(SpringActorProducer.class,
                            applicationContext,
                            actorClass);
    }
}

Now, instead of creating the actors like this….

ActorRef master = actorSystem.actorOf(
                      Props.create(Master.class), "master");

ActorRef workerRouter = getContext().actorOf(
                            Props.create(Worker.class)
                                 .withRouter(new RoundRobinPool(5)),
                            "workerRouter");

… we will use the auto-wired SpringProps to create the actors…

@Autowire
private SpringProps springProps;

...

ActorRef master = actorSystem.actorOf(
                      springProps.create(Master.class), "master");

ActorRef workerRouter = getContext().actorOf(
                            springProps.create(Worker.class)
                                       .withRouter(new RoundRobinPool(5)),
                            "workerRouter");

Make sure all actor classes are Spring-managed with prototype-scoped by annotating them with @Component and @Scope("prototype").

To see the full example, visit https://github.com/choonchernlim/test-akka-spring

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Akka – My Shitty Code

Akka: Spring Integration

PROBLEM

SOLUTION