我试图在演员死亡时发送消息。使用DeathWatch杀死Akka actor时发送的消息
这是基于阿卡临终看护文档: http://doc.akka.io/docs/akka/2.3.6/java/untyped-actors.html#deathwatch-java
在serviceActor我等待“杀”的消息,但我从来没有真正发送此消息。所以要在ServiceActor收到消息我用:
else if (msg instanceof Terminated) {
final Terminated t = (Terminated) msg;
if (t.getActor() == child) {
lastSender.tell(Msg.TERMINATED, getSelf());
}
} else {
unhandled(msg);
}
我已经设置持续时间10毫秒:
Duration.create(10, TimeUnit.MILLISECONDS)
但该消息Msg.TERMINATED
永远不会在的onReceive方法获得:
@Override
public void onReceive(Object msg) {
if (msg == ServiceActor.Msg.SUCCESS) {
System.out.println("Success");
getContext().stop(getSelf());
} else if (msg == ServiceActor.Msg.TERMINATED) {
System.out.println("Terminated");
} else
unhandled(msg);
}
当ServiceActor失败时,如何向HelloWorld发送消息?
整个代码:
package terminatetest;
import akka.Main;
public class Launcher {
public static void main(String args[]) {
String[] akkaArgsArray = new String[1];
akkaArgsArray[0] = "terminatetest.HelloWorld";
Main.main(akkaArgsArray);
}
}
package terminatetest;
import java.util.concurrent.TimeUnit;
import scala.concurrent.duration.Duration;
import akka.actor.ActorRef;
import akka.actor.PoisonPill;
import akka.actor.Props;
import akka.actor.UntypedActor;
public class HelloWorld extends UntypedActor {
@Override
public void preStart() {
int counter = 0;
akka.actor.ActorSystem system = getContext().system();
final ActorRef greeter = getContext().actorOf(
Props.create(ServiceActor.class), String.valueOf(counter));
system.scheduler().scheduleOnce(
Duration.create(10, TimeUnit.MILLISECONDS), new Runnable() {
public void run() {
greeter.tell(PoisonPill.getInstance(), getSelf());
}
}, system.dispatcher());
greeter.tell("http://www.google.com", getSelf());
counter = counter + 1;
}
@Override
public void onReceive(Object msg) {
if (msg == ServiceActor.Msg.SUCCESS) {
System.out.println("Success");
getContext().stop(getSelf());
} else if (msg == ServiceActor.Msg.TERMINATED) {
System.out.println("Terminated");
} else
unhandled(msg);
}
}
package terminatetest;
import static com.utils.PrintUtils.println;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import akka.actor.ActorRef;
import akka.actor.Props;
import akka.actor.Terminated;
import akka.actor.UntypedActor;
public class ServiceActor extends UntypedActor {
final ActorRef child = this.getContext().actorOf(Props.empty(), "child");
{
this.getContext().watch(child);
}
ActorRef lastSender = getContext().system().deadLetters();
public static enum Msg {
SUCCESS, FAIL, TERMINATED;
}
@Override
public void onReceive(Object msg) {
if (msg instanceof String) {
String urlName = (String) msg;
try {
long startTime = System.currentTimeMillis();
URL url = new URL(urlName);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.connect();
BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));
StringBuilder out = new StringBuilder();
String line;
while ((line = reader.readLine()) != null) {
out.append(line);
}
System.out.println("Connection successful to " + url);
System.out.println("Content is " + out);
long endTime = System.currentTimeMillis();
System.out.println("Total Time : " + (endTime - startTime) + " milliseconds");
} catch (MalformedURLException mue) {
println("URL Name " + urlName);
System.out.println("MalformedURLException");
System.out.println(mue.getMessage());
mue.printStackTrace();
getSender().tell(Msg.FAIL, getSelf());
} catch (IOException ioe) {
println("URL Name " + urlName);
System.out.println("IOException");
System.out.println(ioe.getMessage());
ioe.printStackTrace();
System.out.println("Now exiting");
getSender().tell(Msg.FAIL, getSelf());
}
}
else if (msg instanceof Terminated) {
final Terminated t = (Terminated) msg;
if (t.getActor() == child) {
lastSender.tell(Msg.TERMINATED, getSelf());
}
} else {
unhandled(msg);
}
}
}
更新:
更新到ServiceActor:
if (urlName.equalsIgnoreCase("poisonPill")) {
this.getSelf().tell(PoisonPill.getInstance(), getSelf());
getSender().tell(Msg.TERMINATED, getSelf());
}
更新到的HelloWorld 我现在从儿童演员本身使用启动poisonPill:
system.scheduler().scheduleOnce(
Duration.create(10, TimeUnit.MILLISECONDS), new Runnable() {
public void run() {
greeter.tell("poisonPill", getSelf());
}
}, system.dispatcher());
个
这显示下面的输出:经过10毫秒被发送
startTime : 1412777375414
Connection successful to http://www.google.com
Content is ....... (I'veremoved the content for brevity)
Total Time : 1268 milliseconds
Terminated
的poisonPill消息和用于该示例中,演员住为1268毫秒。那么为什么演员在poisonPill发送时没有终止?这是因为时间很短?
更新代码:
package terminatetest;
import java.util.concurrent.TimeUnit;
import scala.concurrent.duration.Duration;
import akka.actor.ActorRef;
import akka.actor.Props;
import akka.actor.UntypedActor;
public class HelloWorld extends UntypedActor {
@Override
public void preStart() {
int counter = 0;
akka.actor.ActorSystem system = getContext().system();
final ActorRef greeter = getContext().actorOf(
Props.create(ServiceActor.class), String.valueOf(counter));
system.scheduler().scheduleOnce(
Duration.create(10, TimeUnit.MILLISECONDS), new Runnable() {
public void run() {
greeter.tell("poisonPill", getSelf());
}
}, system.dispatcher());
greeter.tell("http://www.google.com", getSelf());
counter = counter + 1;
}
@Override
public void onReceive(Object msg) {
if (msg == ServiceActor.Msg.SUCCESS) {
System.out.println("Success");
getContext().stop(getSelf());
} else if (msg == ServiceActor.Msg.TERMINATED) {
System.out.println("Terminated");
} else
unhandled(msg);
}
}
package terminatetest;
import static com.utils.PrintUtils.println;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import akka.actor.ActorRef;
import akka.actor.PoisonPill;
import akka.actor.UntypedActor;
public class ServiceActor extends UntypedActor {
ActorRef lastSender = getSender();
public static enum Msg {
SUCCESS, FAIL, TERMINATED;
}
@Override
public void onReceive(Object msg) {
if (msg instanceof String) {
String urlName = (String) msg;
if (urlName.equalsIgnoreCase("poisonPill")) {
this.getSelf().tell(PoisonPill.getInstance(), getSelf());
getSender().tell(Msg.TERMINATED, getSelf());
}
else {
try {
long startTime = System.currentTimeMillis();
System.out.println("startTime : "+startTime);
URL url = new URL(urlName);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.connect();
BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));
StringBuilder out = new StringBuilder();
String line;
while ((line = reader.readLine()) != null) {
out.append(line);
}
System.out.println("Connection successful to " + url);
System.out.println("Content is " + out);
long endTime = System.currentTimeMillis();
System.out.println("Total Time : " + (endTime - startTime) + " milliseconds");
} catch (MalformedURLException mue) {
println("URL Name " + urlName);
System.out.println("MalformedURLException");
System.out.println(mue.getMessage());
mue.printStackTrace();
getSender().tell(Msg.FAIL, getSelf());
} catch (IOException ioe) {
println("URL Name " + urlName);
System.out.println("IOException");
System.out.println(ioe.getMessage());
ioe.printStackTrace();
System.out.println("Now exiting");
getSender().tell(Msg.FAIL, getSelf());
}
}
}
}
}
谢谢,我已经更新了poisonPill的发送方式 - 它现在作为一个String消息发送,当actor收到“poisonPill”时它自行终止:this.getSelf()。tell(PoisonPill.getInstance(),getSelf )); 。但是,这似乎也不工作,我已更新问题,包括这一点,你可以看看吗? – 2014-10-08 14:17:54
@ blue-sky,增加了更多的细节...... – cmbaxter 2014-10-08 14:26:02
所以通过这个推理“你不能阻止一个演员在它正在做什么。”一个演员不能在N秒后停止? – 2014-10-08 15:00:51