akka入门-有类型的Actor

Akka 中的有类型 Actor 是 Active Objects 模式的一种实现. Smalltalk诞生之时，就已经缺省地将方法调用从同步操作发为异步派发。

有类型 Actor 由两 “部分”组成, 一个公开的接口和一个实现。对普通actor来说，你拥有一个外部API (公开接口的实例) 来将方法调用异步地委托给其实现的私有实例。

有类型Actor相对于普通Actor的优势在于有类型Actor拥有静态的契约, 你不需要定义你自己的消息, 它的劣势在于对你能做什么和不能做什么进行了一些限制，例如你不能使用 become/unbecome。

有类型Actor是使用 JDK Proxies 实现的，JDK Proxies提供了非常简单的api来拦截方法调用。

1.创建接口

import scala.concurrent.Future;import akka.japi.Option;/** * @author lcq * */public interface Squarer {  void squareDontCare( int i ); // 不关心的处理逻辑 fire-and-forget like ActorRef.tell  Future<Integer> square(int i); // non-blocking send-request-reply like ActorRef.ask  Option<Integer> squareNowPlease( int i );// blocking send-request-reply  int squareNow( int i ); // blocking send-request-reply  // Any other type of value -->send-request-reply}

2.实现类

import org.slf4j.Logger;import org.slf4j.LoggerFactory;import scala.concurrent.Future;import akka.dispatch.Futures;import akka.japi.Option;public class SquarerImpl implements Squarer {  public static final Logger log = LoggerFactory.getLogger(SquarerImpl. class);  private String name;  public SquarerImpl() {    this. name = "default";  }  public SquarerImpl(String name) {    this. name = name;  }  public void squareDontCare(int i) {    try {      for ( int j = 0; j < 3; j++) {        Thread. sleep(1000);        log.info("squareDontCare is call " + j );      }    } catch (InterruptedException e) {      e.printStackTrace();    }    int sq = i * i; // Nobody cares :(  }  public Future<Integer> square( int i ) {    try {      Thread.sleep(2000);    } catch (InterruptedException e) {      e.printStackTrace();    }    return Futures. successful(Integer.valueOf (i * i ));  }  public Option<Integer> squareNowPlease( int i ) {    return Option. some(i * i);  }  public int squareNow(int i) {    return i * i;  }}

3.测试类

import org.slf4j.Logger;import org.slf4j.LoggerFactory;import scala.concurrent.ExecutionContext;import scala.concurrent.Future;import akka.actor.ActorSystem;import akka.actor.TypedActor;import akka.actor.TypedProps;import akka.dispatch.OnComplete;import akka.japi.Option;/** * * @author lcq * */public class System {  public static final Logger log = LoggerFactory.getLogger(System.class);  public static void main(String... args) throws Exception {    final ActorSystem actorSystem = ActorSystem.create("actor-system");    Thread.sleep(2000);    // 阻塞方式调用    Squarer mySquarer = TypedActor.get(actorSystem).typedActorOf( new TypedProps<SquarerImpl>(Squarer.class , SquarerImpl.class));    int sqNowValue = mySquarer.squareNow(5);    log.info( "sqNowValue" + sqNowValue );    // 非阻塞方式调用    Future<Integer> fu = mySquarer.square(6);    // ExecutionContext类似于 java.util.concurrent.Executor    final ExecutionContext ec = actorSystem.dispatcher();    // Future的onComplete, onResult, 或 onTimeout 方法可以用来注册一个回调，以便在Future完成时得到通知。从而提供一种避免阻塞的方法。    fu.onComplete( new OnComplete<Integer>() {      @Override      public void onComplete(Throwable failure , Integer result) throws Throwable {        if (failure != null) {          // We got a failure, handle it here        } else {          log.info("square result:" + result );        }      }    }, ec);    log.info( "22222222");    // 阻塞方式调用    Option<Integer> op = mySquarer.squareNowPlease(7);    log.info( "squareNowPlease result : " + op .get());    log.info( "33333333");    // 不关心的处理,方法会在另一个线程中异步地调用    mySquarer.squareDontCare(2);    log.info( "44444444");    Thread.sleep(2000);    log.debug( "Actor System Shutdown Starting..." );    actorSystem.shutdown();  }}

4.输出结果

20:53:31.550 [main] INFO  com.center.akka.typedActors.System - sqNowValue2520:53:31.554 [main] INFO  com.center.akka.typedActors.System - 2222222220:53:33.561 [actor-system-akka.actor.default-dispatcher-4] INFO  com.center.akka.typedActors.System - square result:3620:53:33.562 [main] INFO  com.center.akka.typedActors.System - squareNowPlease result : 4920:53:33.562 [main] INFO  com.center.akka.typedActors.System - 3333333320:53:33.562 [main] INFO  com.center.akka.typedActors.System - 4444444420:53:34.562 [actor-system-akka.actor.default-dispatcher-2] INFO  c.c.akka.typedActors.SquarerImpl - squareDontCare is call 020:53:35.562 [actor-system-akka.actor.default-dispatcher-2] INFO  c.c.akka.typedActors.SquarerImpl - squareDontCare is call 120:53:35.562 [main] DEBUG com.center.akka.typedActors.System - Actor System Shutdown Starting...20:53:36.562 [actor-system-akka.actor.default-dispatcher-2] INFO  c.c.akka.typedActors.SquarerImpl - squareDontCare is call 2