GWT事件处理：针对侦听器类的选择性实例触发事件

Question

Background:

We have an application using GWT and the GWTP framework providing the MVP architecture. We use GWT 's EventBus to broadcast events across presenters.

Requirement:

We have an event called RefreshEvent . The class/presenter firing the event is Parent(P) and the presenter listening to this event is Child(C) . We are running into a situation in the application where multiple instances of the C (the listener) are active at the same time in the application. Let's say instance A and instance B of presenter C are active and both are listening for the RefreshEvent . But in a given context in the application I want to selectively fire the event. That is a RefreshEvent fired by P should be received only by instance A of Child C and not by instance B of Child C .

Does GWT provide any mechanism to do this? If not, how can I achieve this. Our application heavily uses events for inter presenter communication.

Answer 1

Typically, EventBus is used to "broadcast" an event to each party that listens to it (in your example, all instances of your Child C).

If you want a single relationship, your parent can simply call the necessary child:

private Child a;
private Child b;
...
public void on onRefresh() {
    /*
     *  If you need to call child a, call a.doSomething();
     *  If you need to call child b, call b.doSomething();
     */
}