다음과 같은 간단한 액트를 설계해보자
- 인사를 받아주는 액트(Greeter)
- 인사에 반응하여 로그를 찍는 액트( Printer)
Greeter
package com.psmon.akka.study;
import com.psmon.akka.study.Printer.Greeting;
import akka.actor.AbstractActor;
import akka.actor.ActorRef;
import akka.actor.Props;
//#greeter-messages
public class Greeter extends AbstractActor {
//#greeter-messages
static public Props props(String message, ActorRef printerActor) {
return Props.create(Greeter.class, () -> new Greeter(message, printerActor));
}
//#greeter-messages
static public class WhoToGreet {
public final String who;
public WhoToGreet(String who) {
this.who = who;
}
}
static public class Greet {
public Greet() {
}
}
//#greeter-messages
private final String message;
private final ActorRef printerActor;
private String greeting = "";
public Greeter(String message, ActorRef printerActor) {
this.message = message;
this.printerActor = printerActor;
}
@Override
public Receive createReceive() {
return receiveBuilder()
.match(WhoToGreet.class, wtg -> {
this.greeting = message + ", " + wtg.who;
})
.match(Greet.class, x -> {
//#greeter-send-message
printerActor.tell(new Greeting(greeting), getSelf());
//#greeter-send-message
})
.build();
}
//#greeter-messages
}
//#greeter-messages
메시지처리기를 잘 살펴보면, if및 switch문이 없는것을 볼수가 있으며
이러한 분기 처리기법을 패턴매칭이라고도 합니다. 모던한 언어스펙이 여러가지모습 으로
지원하는 컨셉이며 익숙하지 않는다고 하면 전통적인 방식으로 메시처리도 가능합니다.
차이점은 베이스가 되는 액터( AbstractActor or UntypedActor ) 가 누구냐에따라 메시지분기처리에대한
방법을 변경할수가 있습니다.
public class TestActor extends UntypedActor { private final LoggingAdapter log = Logging .getLogger(getContext().system(), "TestActor"); @Override public void onReceive(Object message) throws Exception { if(message instanceof String) { //String뿐만 아니라 모든 Java객체 통신가능 log.info("Incommessage {}", message); sender().tell("너의 메시지에 응답을함", ActorRef.noSender()); }else { log.info("Unhandle Message {}", message); } } }
GreeterPrinter
package com.psmon.akka.study;
import akka.actor.AbstractActor;
import akka.actor.ActorRef;
import akka.actor.Props;
import akka.event.Logging;
import akka.event.LoggingAdapter;
//#printer-messages
public class Printer extends AbstractActor {
//#printer-messages
static public Props props() {
return Props.create(Printer.class, () -> new Printer());
}
//#printer-messages
static public class Greeting {
public final String message;
public Greeting(String message) {
this.message = message;
}
}
//#printer-messages
private LoggingAdapter log = Logging.getLogger(getContext().getSystem(), this);
public Printer() {
}
@Override
public Receive createReceive() {
return receiveBuilder()
.match(Greeting.class, greeting -> {
log.info(greeting.message);
})
.build();
}
//#printer-messages
}
//#printer-messages
수행
package com.psmon.akka.study;
import akka.actor.ActorRef;
import akka.actor.ActorSystem;
import java.io.IOException;
import com.psmon.akka.study.Greeter.*;
public class AkkaQuickstart {
public static void main(String[] args) {
final ActorSystem system = ActorSystem.create("helloakka");
try {
//#create-actors
final ActorRef printerActor =
system.actorOf(Printer.props(), "printerActor");
final ActorRef howdyGreeter =
system.actorOf(Greeter.props("Howdy", printerActor), "howdyGreeter");
final ActorRef helloGreeter =
system.actorOf(Greeter.props("Hello", printerActor), "helloGreeter");
final ActorRef goodDayGreeter =
system.actorOf(Greeter.props("Good day", printerActor), "goodDayGreeter");
//#create-actors
//#main-send-messages
howdyGreeter.tell(new WhoToGreet("Akka"), ActorRef.noSender());
howdyGreeter.tell(new Greet(), ActorRef.noSender());
howdyGreeter.tell(new WhoToGreet("Lightbend"), ActorRef.noSender());
howdyGreeter.tell(new Greet(), ActorRef.noSender());
helloGreeter.tell(new WhoToGreet("Java"), ActorRef.noSender());
helloGreeter.tell(new Greet(), ActorRef.noSender());
goodDayGreeter.tell(new WhoToGreet("Play"), ActorRef.noSender());
goodDayGreeter.tell(new Greet(), ActorRef.noSender());
//#main-send-messages
System.out.println(">>> Press ENTER to exit <<<");
System.in.read();
} catch (IOException ioe) {
} finally {
system.terminate();
}
}
}
위 코드는 AKKA QUCIK START에 의해 자동 생성된 코드입니다.
https://developer.lightbend.com/start/?group=akka&project=akka-quickstart-java