Akka Typed: первые шаги с типизированными актерами в Scala

Это позволит задействовать необходимые основные библиотеки Akka и новый способ создания актеров Akka Typed. После добавления мы можем создать нашего первого актера. Одно из самых больших отличий заключается в том, что мы больше не создаем актеров в явном виде, но мы определяем поведение и исходя из этого поведения мы создаем актера. Чтобы упростить вам задачу, Akka Typed предлагает множество вспомогательных классов, облегчающих определение поведения. В этой статье мы представим ряд из них.

Простое статическое поведение

Сначала давайте посмотрим на код для простого статического актера. Обратите внимание, что мы показываем некоторые дополнительные классы case, чтобы сделать примеры немного более полезными:

  import scala.concurrent.ExecutionContext.Implicits.global
  implicit val timeout = Timeout(5 seconds)

  // 1. First simple example, we'll create a typed actor
  // which just prints out the received message.
  println("Step 1: Using static Actor")

  // which can only receive HelloMsg message.
  sealed trait HelloMsg
  final case class HelloCountry(country: String) extends HelloMsg
  final case class HelloCity(city: String) extends HelloMsg
  final case class HelloWorld() extends HelloMsg
  final case class Hello(msg: String) extends HelloMsg

  // simple static actor, which just prints out the message
  val helloSayer = Static[HelloMsg] { msg =>
    println("Msg received:" + msg);
  }

  // create a new root actor and send it types messages
  val helloSystem: ActorSystem[HelloMsg] = ActorSystem("helloSayer", Props(helloSayer))
  helloSystem ! HelloCountry("Netherlands")
  helloSystem ! HelloWorld()
  helloSystem ! HelloCity("Waalwijk")
  helloSystem ! Hello("HelloHelloHello")

Step 1: Using static Actor
Msg received:HelloCountry(Netherlands)
Msg received:HelloWorld()
Msg received:HelloCity(Waalwijk)
Msg received:Hello(HelloHelloHello)

  // 2. Now we use an actor that responds to the sending actor using the
  // ask pattern.
  Thread.sleep(1000)
  println("\n\nStep 2: Using reply Actor")

  // Simple case class, which is used for the ask pattern
  final case class HelloReply(say: String, replyTo: ActorRef[HelloMsg])

  // static actor that responds to the passed in actorRef
  val helloReplyer = Static[HelloReply] {msg =>
    msg.replyTo ! Hello(s"You said: ${msg.say} ")
  }

  // create a new system and use the ask pattern to send it messages.
  val replySystem: ActorSystem[HelloReply] = ActorSystem("hello", Props(helloReplyer))
  val response = replySystem ? { f:ActorRef[HelloMsg] => HelloReply("Hello", f)}
  // or use a shorter form: val response = replySystem ? (HelloReply("Hello", _))
  val res = Await.result(response, 5 seconds)
  println("Response recevied: " + res)

Step 2: Using reply Actor
Response recevied: Hello(You said: Hello )

  val fullBehavior = ContextAware[HelloMsg] { ctx =>
    println(s"We can access the context: $ctx")
    Full[HelloMsg] {
      case msg: MessageOrSignal[HelloMsg] => println(s"Recevied messageOrSignal: $msg"); Same[HelloMsg]
    }
  }

  val fullSystem: ActorSystem[HelloMsg] = ActorSystem("hello", Props(fullBehavior))
  fullSystem ! HelloCountry("Netherlands")
  fullSystem ! HelloWorld()
  fullSystem ! HelloCity("Waalwijk")
  fullSystem ! Hello("HelloHelloHello")

in total function: hellocountry(netherlands)
IN TOTAL FUNCTION: HELLOWORLD()
in total function: hellocity(waalwijk)
IN TOTAL FUNCTION: HELLO(HELLOHELLOHELLO)

  val fullBehavior = ContextAware[HelloMsg] { ctx =>
    println(s"We can access the context: $ctx")
    Full[HelloMsg] {
      case msg: MessageOrSignal[HelloMsg] => println(s"Recevied messageOrSignal: $msg"); Same[HelloMsg]
    }
  }

  val fullSystem: ActorSystem[HelloMsg] = ActorSystem("hello", Props(fullBehavior))
  fullSystem ! HelloCountry("Netherlands")
  fullSystem ! HelloWorld()
  fullSystem ! HelloCity("Waalwijk")
  fullSystem ! Hello("HelloHelloHello")

We can access the context: akka.typed.ActorContextAdapter@ee559a3
Recevied messageOrSignal: Sig(akka.typed.ActorContextAdapter@ee559a3,PreStart)
Recevied messageOrSignal: Msg(akka.typed.ActorContextAdapter@ee559a3,HelloCountry(Netherlands))
Recevied messageOrSignal: Msg(akka.typed.ActorContextAdapter@ee559a3,HelloWorld())
Recevied messageOrSignal: Msg(akka.typed.ActorContextAdapter@ee559a3,HelloCity(Waalwijk))
Recevied messageOrSignal: Msg(akka.typed.ActorContextAdapter@ee559a3,Hello(HelloHelloHello))

// when the system is shutdown
Recevied messageOrSignal: Sig(akka.typed.ActorContextAdapter@ee559a3,PostStop)

  val andCombined = helloSayer && behavior1
  val andSystem: ActorSystem[HelloMsg] = ActorSystem("and",Props(andCombined))
  andSystem ! HelloCountry("Netherlands")
  andSystem ! HelloWorld()
  andSystem ! HelloCity("Waalwijk")
  andSystem ! Hello("HelloHelloHello")


  Thread.sleep(1000)
  println("\n\nStep 5a: Use the || combinator")
  // first try the left one, if it is unhandled tries the right one
  val orCombined = Total[HelloMsg]{
    case _ => {println("Can't handle it here!");Unhandled}
  } || fullBehavior
  val orSystem: ActorSystem[HelloMsg] = ActorSystem("or", Props(orCombined))
  orSystem ! HelloCountry("Netherlands")
  orSystem ! HelloWorld()
  orSystem ! HelloCity("Waalwijk")
  orSystem ! Hello("HelloHelloHello")

Msg received:HelloCountry(Netherlands)
in total function: hellocountry(netherlands)
Msg received:HelloWorld()
IN TOTAL FUNCTION: HELLOWORLD()
Msg received:HelloCity(Waalwijk)
in total function: hellocity(waalwijk)
Msg received:Hello(HelloHelloHello)
IN TOTAL FUNCTION: HELLO(HELLOHELLOHELLO)

We can access the context: akka.typed.ActorContextAdapter@4cba0952
Recevied messageOrSignal: Sig(akka.typed.ActorContextAdapter@4cba0952,PreStart)
Can't handle it here!
Recevied messageOrSignal: Msg(akka.typed.ActorContextAdapter@4cba0952,HelloCountry(Netherlands))
Can't handle it here!
Recevied messageOrSignal: Msg(akka.typed.ActorContextAdapter@4cba0952,HelloWorld())
Can't handle it here!
Recevied messageOrSignal: Msg(akka.typed.ActorContextAdapter@4cba0952,HelloCity(Waalwijk))
Can't handle it here!
Recevied messageOrSignal: Msg(akka.typed.ActorContextAdapter@4cba0952,Hello(HelloHelloHello))