EDA a simple example with Sculptor continued

Lets continue with our simple example from the last post. We declared a domain event in the model and we marked a service to publish that event to a channel.

Now, what about getting notified when such an event is published?

Continuing with our model from last time, its just a matter of editing it. Lets create another module with a service that is interested of the event:

Application Universe {
 basePackage=org.helloworld

 Module milkyway {
   Service PlanetService {
     @BigLandingSuccess landOnPlanet(String planetName, String astronautName)
       publish to milkywayChannel;
   }

   DomainEvent BigLandingSuccess {
     String planetName
     String astronautName
   }
 }
 Module houston {
   Service GroundControlService {
     subscribe to milkywayChannel
     bringOutTheChampagne(int noOfBottles);
   }
 }
}

The result is that the GroundControl service will implement the EventSubscriber interface and be marked with @Subscribe annotation. That means that the GroundControl service will automatically be added as subscriber to milkywayChannel. It will be notified, receive method called, when events are published to that channel.

You will get a stub of the receive method of the EventSubscriber interface.

@Override
public void receive(Event event) {
 // TODO Auto-generated method stub
 throw new UnsupportedOperationException("receive not implemented");
}

So that you will need to implement with your logic:

@Override
public void receive(Event event) {
 if (event instanceof BigLandingSuccess) {
   this.bringOutTheChampagne(999999);
 }
}

Ok, so now we covered some very simple notations for publishing and subscribing to events. Next time I'll show how to do the same but in plain java code.