CODEWITHSUNDEEP
javaguava
Rishi
Rishi

Reputation: 1351

subscribing to an event bus

I am trying to use guava for subscribing to EventBus. Trying to look at the site doc but unable to see any example where it shows how to do it.

Anyone tried this before??

private final EventBus eventBus = new EventBus();
eventBus.post(eventId); // where eventId is a string.

This is being in one of the jars. Now I need to subscribe to this eventbus and check if there are any new eventId's posted. How can I do that?

Any help is appreciated.

Thanks!!

Upvotes: 4

Views: 12964

Answers (2)

sam zhou
sam zhou

Reputation: 1

Here is a simple demo.

public class EventBusDemo{

public static void main(String[] args) {
    handleTransaction();
}

public static void handleTransaction() {
    CatSubscriber catSubscriber = new CatSubscriber();
    PandaSubscriber pandaSubscriber = new PandaSubscriber();
    DogSubscriber dogSubscriber = new DogSubscriber();
    EventBus eventBus = new EventBus();
    Animal cat = new Cat();
    Animal dog = new Dog();
    Animal panda = new Panda();
    eventBus.register(pandaSubscriber);
    eventBus.register(catSubscriber);
    eventBus.register(dogSubscriber);

    eventBus.post(cat);
    eventBus.post(dog);
    eventBus.post(panda);

}

}

interface Animal {

void run();

}

class Cat implements Animal {

@Override
public void run() {
    try {
        Thread.sleep(2000);
    } catch (InterruptedException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    // TODO Auto-generated method stub
    System.out.println(Cat.class.getSimpleName() + " run");
}

}

class CatSubscriber {

@Subscribe
public void catRun(Animal animal) {
    animal.run();
}

}

class Dog implements Animal {

@Override
public void run() {
    try {
        Thread.sleep(2000);
    } catch (InterruptedException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    // TODO Auto-generated method stub
    System.out.println(Dog.class.getSimpleName() + " run");
}

}

class DogSubscriber {

@Subscribe
public void dogRun(Animal animal) {
    animal.run();

}

}

class Panda implements Animal {

@Override
public void run() {
    try {
        Thread.sleep(2000);
    } catch (InterruptedException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    // TODO Auto-generated method stub
    System.out.println(Panda.class.getSimpleName() + " run");
}

}

class PandaSubscriber {

@Subscribe
public void pandaRun(Animal animal) {
    animal.run();
}

}

Upvotes: 0

ColinD
ColinD

Reputation: 110054

You would need some object with a method annotated @Subscribe that takes a parameter of type String (since you're posting a String as an event to it... note that some more specific event type is probably preferable). You then need to pass that object to the EventBus.register(Object) method. Example:

public class Foo {
  @Subscribe
  public void handleEvent(String eventId) {
    // do something
  }
}

Foo foo = ...
eventBus.register(foo);
eventBus.post(eventId);

Upvotes: 9

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