Java Pattern - Exception propagation in actor hierarchy using supervision

Ticket #2605

akka-docs/rst/java/code/docs/pattern/JavaAsk.java

@@ -0,0 +1,45 @@
+public class JavaAsk extends UntypedActor {
+    private ActorRef targetActor;
+    private ActorRef caller;
+    
+    private static class AskParam {
+        Props props;
+        Object message;
+        AskParam(Props props, Object message) {
+            this.props = props;
+            this.message = message;
+        }
+    }
+    
+    @Override
+    public SupervisorStrategy supervisorStrategy() {
+        return new OneForOneStrategy(0, Duration.Zero(), new Function<Throwable, Directive>() {
+            public Directive apply(Throwable cause) {
+                caller.tell(new Status.Failure(cause));
+                return SupervisorStrategy.stop();
+            }
+        });
+    }
+
+    @Override
+    public void onReceive(Object message) throws Exception {
+        if (message instanceof AskParam) {
+            AskParam param = (AskParam) message;
+            caller = getSender();
+            targetActor = getContext().actorOf(param.props);
+            targetActor.forward(param.message, getContext());
+        } else
+            unhandled(message);
+    }
+
+    public static void ask(ActorSystem system, Props props, Object message, Timeout timeout) throws Exception {
+        ActorRef javaAsk = system.actorOf(Props.apply(JavaAsk.class));
+        try {
+            AskParam param = new AskParam(props, message);
+            Future<Object> finished = Patterns.ask(javaAsk, param, timeout);
+            Await.result(finished, timeout.duration());
+        } finally {
+            system.stop(javaAsk);
+        }
+    }
+}