我已经开始在 Scala 中使用 TypedActors,并且在做一些非常简单的事情时遇到了问题:我希望 Actor A 调用 Actor B 上的方法并在 Actor A 上的匿名函数中处理结果,但要确保:
我怎样才能(或我能)同时满足这两个要求?
例如,这个actor只想调用otherActor上的一个返回Future[Int]的API,并用结果更新它的状态,然后做一些需要它的actor上下文的事情:
class MyActorImpl extends MyActor {
// my mutable state
var myNumber = 0
// method proxied by TypedActor ref:
def doStuff(otherActor: OtherActor): Unit = {
otherActor.doOtherStuff onSuccess {
// oops this is no longer running in MyActorImpl..
// this could be on a concurrent thread if we
case i => processResult(i)
}
}
private def processResult(i: Int): Unit = {
myNumber = 0 // oops, now we are possibly making a concurrent modification
println(s"Got $i")
// fails with java.lang.IllegalStateException: Calling TypedActor.context
// outside of a TypedActor implementation method!
println(s"My context is ${TypedActor.context}")
}
}
我在这里想念什么?我是否需要编写我的处理程序来调用代理接口(interface)上定义的方法以保证单条目?如果我不想在接口(interface)上公开那个特定的“私有(private)”方法(例如 processResult),那看起来会很丑陋。
这是将在 Scala REPL 中运行的完整版本:
import akka.actor._
import scala.concurrent._
val system = ActorSystem("mySystem")
import system.dispatcher
trait OtherActor {
def doOtherStuff(): Future[Int]
}
trait MyActor {
def doStuff(otherActor: OtherActor): Unit
}
class OtherActorImpl extends OtherActor {
var i = 0
def doOtherStuff(): Future[Int] = {
i += 1
Future {i}
}
}
class MyActorImpl extends MyActor {
// my mutable state
var myNumber = 0
// method proxied by TypedActor ref:
def doStuff(otherActor: OtherActor): Unit = {
otherActor.doOtherStuff onSuccess {
// oops this is no longer running in MyActorImpl..
// this could be on a concurrent thread if we
case i => processResult(i)
}
}
private def processResult(i: Int): Unit = {
myNumber = 0 // oops, now we are possibly making a concurrent modification
println(s"Got $i")
// fails with java.lang.IllegalStateException: Calling TypedActor.context
// outside of a TypedActor implementation method!
println(s"My context is ${TypedActor.context}")
}
}
val actor1: MyActor = TypedActor(system).typedActorOf(TypedProps[MyActorImpl])
val actor2: OtherActor = TypedActor(system).typedActorOf(TypedProps[OtherActorImpl])
actor1.doStuff(actor2)
最佳答案
您将 Actor 的状态暴露给外部世界,这是一件非常糟糕的事情。看这里:http://doc.akka.io/docs/akka/2.3.3/general/jmm.html第 9-10 节 Actors and shared mutable state lines 描述了你的情况。
@philwalk 已经描述了如何解决这个问题:Akka TypedActor - how to correctly handle async responses with context
关于scala - Akka TypedActor - 如何正确处理带有上下文的异步响应,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/23306255/