add Event listener to a specific Activity
<p>Upon receiving a GCM Intent in my GcmIntentService I am building a push notification and I have to set a specific Activity as EventListener. </p>

<pre><code>public class GcmIntentService extends IntentService {

    @Override
    protected void onHandleIntent(final Intent intent) {
        //This code gets triggered, what to add here 
        // to make SomeActivity's onEvent get triggered
    }
}


public interface EventListener {
    int onEvent(Event event);
}

public class SomeActivity extends Activity implements EventListener {

    @Override
    public int onEvent(Event event) {

    }
}
</code></pre>