接口方法的注释不会继承到实现该接口的对象afaik。 SO search results 。

我想与Guava的EventBus一起使用一个接口,它要求对象有一个带注释的回调方法 @Subscribe 。 我想知道是否可以简单地将该注释放入接口中,并让对象实现该侦听器接口。根据 above ,这应该 不 工作然而 确实有效 (参见下面的代码)。

为什么?

我的机器是带有Windows 7的Java 1.8.0\u 151(32位)。

import static org.junit.Assert.assertEquals;
import org.junit.Test;
import com.google.common.eventbus.EventBus;
import com.google.common.eventbus.Subscribe;

/**
 * This test should fail, but... it works!
 */
public class EventTests {


    @Test
    public void test_events_are_heard() {

        MyListener listener = new MyListener();
        DeafListener deafListener = new DeafListener();
        EventBus bus = new EventBus();
        bus.register(listener);
        bus.register(deafListener);
        bus.post(new MyEvent());
        assertEquals(1, listener.eventCount);     // ok
        assertEquals(0, deafListener.eventCount);   // ok
    }

    // this interface includes the @Subscribe annotation
    private interface Listener {
        @Subscribe
        public void onEvent(MyEvent event);
    }

    // this interface does not include the @Subscribe annotation
    private interface NoListener {
        public void onEvent(MyEvent event);
    }

    // just something different from Object
    private static class MyEvent {
    }       

    // implementation of "Listener" (with @Subscribe in interface)
    private static class MyListener implements Listener {
        int eventCount = 0;
        @Override
        public void onEvent(MyEvent event) {
            eventCount ++;
        }
    }

    // IDENTICAL implementation as above, but of "NoListener" 
    // (without @Subscribe in interface)
    private static class DeafListener implements NoListener {
        int eventCount = 0;
        @Override
        public void onEvent(MyEvent event) {
            eventCount ++;
        }
    }

}