GWTP EventBus on Non-Presenter Class

In my GWTP Application I have a simple Java class, which is not a Presenter, it's just a single class. From this class, I need to fire an event that will be listened from a Presenter class.

GWTP has a single EventBus shared amongst the presenters. The problem is I need to fire the event from the outside class in this EventBus in order for the presenters to be able to listen to it.

I did my research and so far I haven't encountered a way to share GWTP's EventBus with this external class (except from inside any random presenter, which is not correct).

As I see here, the methods of injecting does not work. Any ideias?

I'll share some code if needed. Thanks!

Here is my Class:

public class MyClass {

private static MyClass INSTANCE;

public static MyClass singleton() {

    if (INSTANCE == null) {
        INSTANCE = new MyClass();
    }
    return INSTANCE;
}

private MyClass() {
}
}

And

@Inject EventBus eventBus

does not work. When I call eventBus.fireEvent(), eventBus is undefined.

Solution

You should rewrite your class and use Gin to bind MyClass as a Singleton with bind(MyClass.class).in(Singleton.class) and inject MyClass where you need it instead. Your MyClass class could then look like this :

public class MyClass {
    @Inject
    MyClass(EventBus eventBus) {
        this.eventBus = eventBus;   
    }
}

If you really want to do your own singleton, then you can also use static injection from a Gin module : requestStaticInjection(MyClass.class).

public class MyClass {
    @Inject
    private static EventBus eventBus;
    private static MyClass INSTANCE;

    public static MyClass singleton() {
        if (INSTANCE == null) {
            INSTANCE = new MyClass();
        }
        return INSTANCE;
    }

    private MyClass() {
    }
}