Guava EventBus多个订阅者相同的tpe

Question

import com.google.common.eventbus.EventBus;
import com.google.common.eventbus.Subscribe;

public class Test {

    public static class Processing { }
    public static class ProcessingResults { }
    public static class ProcessingFinished { }

    public static EventBus bus = new EventBus();

    @Subscribe
    public void receiveStartRequest(Processing evt) {
        System.out.println("Got processing request - starting processing");
    }

    @Subscribe
    public void processingStarted(Processing evt) {
        System.out.println("Processing has started");
    }

    @Subscribe
    public void resultsReceived(ProcessingResults evt) {
        System.out.println("got results");
    }

    @Subscribe
    public void processingComplete(ProcessingFinished evt) {
        System.out.println("Processing has completed");
    }


    public static void main(String[] args) {
        Test t = new Test();
        bus.register(t);
        bus.post(new Processing());
    }
}

因此，在上面的例子中，可以看到有2个订阅者接受相同类型的处理。现在，在post（）时，将调用所有函数？如果将调用2个函数receiveStartRequest和processingStarted，那么它们将以何种顺序被调用？

Answer 1

您的方法都将被调用，并且没有预先确定的顺序。

要解决此问题，只需创建两个额外的类：ProcessingStarted和ProcessingRequested。

public class ProcessingStarted {
  private Processing processing;
  // Constructors
  // Getters/Setters
}


public class ProcessingStarted {
  private Processing processing;
  // Constructors
  // Getters/Setters
}

然后在需要时拨打post(new ProcessingRequested(processing))和post(new ProcessingStarted(processing))，而不是一个post(processing)。