我有以下驱动程序/主类封装我的Akka程序：
// Groovy pseudo-code
class FizzBuzz {
ActorSystem actorSystem
static void main(String[] args) {
FizzBuzz d = new FizzBuzz()
d.run()
}
void run() {
Initialize initCmd = new Initialize()
MasterActor master = actorSystem.get(...)
// Tells the entire actor system to initialize itself and start doing stuff.
// ChickenCluckDetector is an actor managed/supervised by MasterActor.
master.tell(initCmd,...)
}
// Called when a ChickenCluckDetector actor inside the actor system receives
// a 'Cluck' message.
void onChickenGoesCluck(Cluck cluck) {
// Do something
}
}
以下ChickenCluckDetector演员：
class ChickenCluckDetector extends UntypedActor {
@Override
void onReceive(Object message) {
if(message instanceof Cluck) {
Cluck cluck = message as Cluck
// Now,how to pass the message safely/properly to FizzBuzz#onCluck?
}
}
}
所以手头的问题是如何安全/正确地将Cluck消息传递给FizzBuzz#onCluck(Cluck),它存在于actor系统之外？我可以提供一个关于ChickenCluckDetector的FizzBuzz引用,如下所示：
class ChickenCluckDetector extends UntypedActor {
FizzBuzz fizzBuzz
@Override
void onReceive(Object message) {
if(message instanceof Cluck) {
Cluck cluck = message as Cluck
fizzBuzz.onCluck(cluck)
}
}
}
但我有一种感觉,这违反了Akka的最佳实践,可能导致各种基于并发的问题,特别是如果只有一个FizzBuzz(有)非演员/驱动程序,以及一万个ChickenCluckDetector演员.想法？
解决方法
if there’s only one FizzBuzz (which there is) non-actor/driver,and ten thousand ChickenCluckDetector actors
那么最好为所有这些ChickenCluckDetectors创建一个共同的父级.然后,这个父母可以安全地保存对FizzBuzz的引用,从他所有的孩子那里收到cluck并调用onCluck方法.
在演员之外获取消息的一个选择是询问.在Scala中有演员DSL(仅为完整性添加).但我相信你的例子中不需要这些.
public class ChickenCluckMaster extends UntypedActor {
private FizzBuzz fizzBuzz;
public ChickenCluckMaster(FizzBuzz fizzBuzz) {
this.fizzBuzz = fizzBuzz;
}
public void onReceive(Object message) throws Exception {
if (message instanceOf CreateDetector) {
getContext().actorOf(
Props.create(ChickenCluckDetector.class,getSelf); // Create child
} else if (message instanceof Cluck) {
fizzBuzz.onCluck(cluck);
} else {
unhandled(message);
}
}
}
public class ChickenCluckDetector extends UntypedActor {
private ActorRef master;
public ChickenCluckDetector(ActorRef master) {
this.master = master;
}
public void onReceive(Object message) throws Exception {
if (message instanceof Cluck) {
Cluck cluck = (Cluck) message;
master.tell(cluck,getSelf);
} else {
unhandled(message);
}
}
}
