Akka 實踐（二）- java開發demo1__Akka

下面就Akka的一個java demo來說明Akka 如何運作的。 1、首先下載 Akka的官方包

下載地址為： http://akka.io/downloads/.  我下載的是 Akka的2.3.15

     解壓這個壓縮包，準備拷貝相關的jar包到自己的工程 2、建立一個java工程

     首先匯入包

      3、下面是源碼和源碼說明

這裡，首先貼入源碼，然後再對源碼進行分析。 源碼有4個檔案，主要完成的功能是，主程式建立ActorSystem，並且產生Actor1（CreationActor），這個Actor1，根據隨機得到的訊息，迴圈建立線程，每個線程都建立Actor2（CalculatorActor），並發不同的訊息給Actor2 告訴這些第二層Actor要做什麼。 這些Actor2 做完自己的事情後，發訊息給Actor1,告訴自己完成了，Actor1 收到訊息後，列印結果是什麼，並結束線程。

整個業務大致可以用下面圖來表示：（左邊是示意圖，右邊是類圖）

Op.java

<span style="font-family:Microsoft YaHei;font-size:14px;">package com.cwqsolo.study.akka.demo;import java.io.Serializable;//Op 類是操作類，分別包含了 加減乘除類和加減乘除結果類public class Op {  public interface MathOp extends Serializable {  }  public interface MathResult extends Serializable {  }  //加法操作  static class Add implements MathOp {    private static final long serialVersionUID = 1L;    private final int n1;    private final int n2;    public Add(int n1, int n2) {      this.n1 = n1;      this.n2 = n2;    }    public int getN1() {      return n1;    }    public int getN2() {      return n2;    }  }  static class AddResult implements MathResult {    private static final long serialVersionUID = 1L;    private final int n1;    private final int n2;    private final int result;    public AddResult(int n1, int n2, int result) {      this.n1 = n1;      this.n2 = n2;      this.result = result;    }    public int getN1() {      return n1;    }    public int getN2() {      return n2;    }    public int getResult() {      return result;    }  }  //減法操作  static class Subtract implements MathOp {    private static final long serialVersionUID = 1L;    private final int n1;    private final int n2;    public Subtract(int n1, int n2) {      this.n1 = n1;      this.n2 = n2;    }    public int getN1() {      return n1;    }    public int getN2() {      return n2;    }  }  static class SubtractResult implements MathResult {    private static final long serialVersionUID = 1L;    private final int n1;    private final int n2;    private final int result;    public SubtractResult(int n1, int n2, int result) {      this.n1 = n1;      this.n2 = n2;      this.result = result;    }    public int getN1() {      return n1;    }    public int getN2() {      return n2;    }    public int getResult() {      return result;    }  }   //乘法操作  static class Multiply implements MathOp {    private static final long serialVersionUID = 1L;    private final int n1;    private final int n2;    public Multiply(int n1, int n2) {      this.n1 = n1;      this.n2 = n2;    }    public int getN1() {      return n1;    }    public int getN2() {      return n2;    }  }  static class MultiplicationResult implements MathResult {    private static final long serialVersionUID = 1L;    private final int n1;    private final int n2;    private final int result;    public MultiplicationResult(int n1, int n2, int result) {      this.n1 = n1;      this.n2 = n2;      this.result = result;    }    public int getN1() {      return n1;    }    public int getN2() {      return n2;    }    public int getResult() {      return result;    }  }  // 除法操作  static class Divide implements MathOp {    private static final long serialVersionUID = 1L;    private final double n1;    private final int n2;    public Divide(double n1, int n2) {      this.n1 = n1;      this.n2 = n2;    }    public double getN1() {      return n1;    }    public int getN2() {      return n2;    }  }  static class DivisionResult implements MathResult {    private static final long serialVersionUID = 1L;    private final double n1;    private final int n2;    private final double result;    public DivisionResult(double n1, int n2, double result) {      this.n1 = n1;      this.n2 = n2;      this.result = result;    }    public double getN1() {      return n1;    }    public int getN2() {      return n2;    }    public double getResult() {      return result;    }  }}</span>

CalculatorActor.java

<span style="font-family:Microsoft YaHei;font-size:14px;">package com.cwqsolo.study.akka.demo;import akka.actor.UntypedActor;public class CalculatorActor extends UntypedActor {        @Override    public void onReceive(Object message) {      if (message instanceof Op.Add) {        Op.Add add = (Op.Add) message;        System.out.println("Calculating " + add.getN1() + " + " + add.getN2());        Op.AddResult result = new Op.AddResult(add.getN1(), add.getN2(),            add.getN1() + add.getN2());        getSender().tell(result, getSelf());      } else if (message instanceof Op.Subtract) {        Op.Subtract subtract = (Op.Subtract) message;        System.out.println("Calculating " + subtract.getN1() + " - "            + subtract.getN2());        Op.SubtractResult result = new Op.SubtractResult(subtract.getN1(),            subtract.getN2(), subtract.getN1() - subtract.getN2());        getSender().tell(result, getSelf());      } else if (message instanceof Op.Multiply) {        Op.Multiply multiply = (Op.Multiply) message;        System.out.println("Calculating " + multiply.getN1() + " * "            + multiply.getN2());        Op.MultiplicationResult result = new Op.MultiplicationResult(            multiply.getN1(), multiply.getN2(), multiply.getN1()                * multiply.getN2());        getSender().tell(result, getSelf());      } else if (message instanceof Op.Divide) {        Op.Divide divide = (Op.Divide) message;        System.out.println("Calculating " + divide.getN1() + " / "            + divide.getN2());        Op.DivisionResult result = new Op.DivisionResult(divide.getN1(),            divide.getN2(), divide.getN1() / divide.getN2());        getSender().tell(result, getSelf());      } else {        unhandled(message);      }    }  }</span>

CreationActor.java

<span style="font-family:Microsoft YaHei;font-size:14px;">package com.cwqsolo.study.akka.demo;import akka.actor.ActorRef;import akka.actor.Props;import akka.actor.UntypedActor;//建立Actorpublic class CreationActor extends UntypedActor {  @Override  public void onReceive(Object message) throws Exception {    if (message instanceof Op.MathOp) {      ActorRef calculator = getContext().actorOf(          Props.create(CalculatorActor.class));      calculator.tell(message, getSelf());    } else if (message instanceof Op.MultiplicationResult) {      Op.MultiplicationResult result = (Op.MultiplicationResult) message;      System.out.printf("Mul result: %d * %d = %d\n", result.getN1(),          result.getN2(), result.getResult());      getContext().stop(getSender());    } else if (message instanceof Op.DivisionResult) {      Op.DivisionResult result = (Op.DivisionResult) message;      System.out.printf("Div result: %.0f / %d = %.2f\n", result.getN1(),          result.getN2(), result.getResult());      getContext().stop(getSender());    } else {      unhandled(message);    }  }}</span>

CreationApplication.java

<span style="font-family:Microsoft YaHei;font-size:14px;">package com.cwqsolo.study.akka.demo;import static java.util.concurrent.TimeUnit.SECONDS;import java.util.Random;import scala.concurrent.duration.Duration;import akka.actor.ActorRef;import akka.actor.ActorSystem;import akka.actor.Props;import com.typesafe.config.ConfigFactory;public class CreationApplication {  public static void main(String[] args) {    if (args.length == 0 || args[0].equals("CalculatorWorker"))      startRemoteWorkerSystem();    if (args.length == 0 || args[0].equals("Creation"))      startRemoteCreationSystem();  }  public static void startRemoteWorkerSystem() {    ActorSystem.create("CalculatorWorkerSystem",        ConfigFactory.load(("calculator")));    System.out.println("Started CalculatorWorkerSystem");  }  public static void startRemoteCreationSystem() {    final ActorSystem system = ActorSystem.create("CreationSystem",        ConfigFactory.load("remotecreation"));    final ActorRef actor = system.actorOf(Props.create(CreationActor.class),        "creationActor");    System.out.println("Started CreationSystem");    final Random r = new Random();    system.scheduler().schedule(Duration.create(1, SECONDS),        Duration.create(1, SECONDS), new Runnable() {          @Override          public void run() {            if (r.nextInt(100) % 2 == 0) {              actor.tell(new Op.Multiply(r.nextInt(100), r.nextInt(100)), null);            } else {              actor.tell(new Op.Divide(r.nextInt(10000), r.nextInt(99) + 1),                  null);            }          }        }, system.dispatcher());  }}</span>

源碼啟動並執行結果為：

Started CalculatorWorkerSystem
Started CreationSystem
Calculating 4915.0 / 63
Div result: 4915 / 63 = 78.02
Calculating 1409.0 / 15
Div result: 1409 / 15 = 93.93
Calculating 99 * 64
Mul result: 99 * 64 = 6336

4、源碼分析  4.1，我們先看一下順序圖表，看看是如何調用的。

4.2 一些關鍵內容的說明

   1、只能建立一個WorkerSystem

    ActorSystem.create("CalculatorWorkerSystem",        ConfigFactory.load(("calculator")));

   2、 只能建立一個ActorSystem

    final ActorSystem system = ActorSystem.create("CreationSystem",    ConfigFactory.load("remotecreation"));

   3、建立Actor

    final ActorRef actor = system.actorOf(Props.create(CreationActor.class),   "creationActor");

   4、發送訊息給這個Actor

    actor.tell(new Op.Multiply(r.nextInt(100), r.nextInt(100)), null);

  5、 Actor 返回訊息給上層調用的Actor

   getSender().tell(result, getSelf());