Improved java version of pi example also. See #1729

This commit is contained in:
Patrik Nordwall 2012-01-26 14:34:31 +01:00
parent c64b73004a
commit fa41cea897
5 changed files with 239 additions and 200 deletions

View file

@ -5,172 +5,193 @@
package akka.tutorial.first.java;
//#imports
import akka.actor.Props;
import akka.actor.ActorRef;
import akka.actor.ActorSystem;
import akka.actor.InternalActorRef;
import akka.actor.Props;
import akka.actor.UntypedActor;
import akka.actor.UntypedActorFactory;
import akka.japi.Creator;
import akka.routing.*;
import akka.util.Timeout;
import akka.routing.RoundRobinRouter;
import akka.util.Duration;
import java.util.concurrent.TimeUnit;
import java.util.LinkedList;
import java.util.concurrent.CountDownLatch;
//#imports
//#app
public class Pi {
public static void main(String[] args) throws Exception {
Pi pi = new Pi();
pi.calculate(4, 10000, 10000);
public static void main(String[] args) {
Pi pi = new Pi();
pi.calculate(4, 10000, 10000);
}
//#actors-and-messages
//#messages
static class Calculate {
}
static class Work {
private final int start;
private final int nrOfElements;
public Work(int start, int nrOfElements) {
this.start = start;
this.nrOfElements = nrOfElements;
}
//#actors-and-messages
//#messages
static class Calculate {
public int getStart() {
return start;
}
static class Work {
private final int start;
private final int nrOfElements;
public int getNrOfElements() {
return nrOfElements;
}
}
public Work(int start, int nrOfElements) {
this.start = start;
this.nrOfElements = nrOfElements;
}
static class Result {
private final double value;
public int getStart() {
return start;
}
public int getNrOfElements() {
return nrOfElements;
}
public Result(double value) {
this.value = value;
}
static class Result {
private final double value;
public Result(double value) {
this.value = value;
}
public double getValue() {
return value;
}
public double getValue() {
return value;
}
//#messages
}
//#worker
public static class Worker extends UntypedActor {
static class PiApproximation {
private final double pi;
private final Duration duration;
//#calculatePiFor
private double calculatePiFor(int start, int nrOfElements) {
double acc = 0.0;
for (int i = start * nrOfElements; i <= ((start + 1) * nrOfElements - 1); i++) {
acc += 4.0 * (1 - (i % 2) * 2) / (2 * i + 1);
}
return acc;
}
//#calculatePiFor
public void onReceive(Object message) {
if (message instanceof Work) {
Work work = (Work) message;
double result = calculatePiFor(work.getStart(), work.getNrOfElements());
getSender().tell(new Result(result));
} else {
throw new IllegalArgumentException("Unknown message [" + message + "]");
}
}
public PiApproximation(double pi, Duration duration) {
this.pi = pi;
this.duration = duration;
}
//#worker
//#master
public static class Master extends UntypedActor {
private final int nrOfMessages;
private final int nrOfElements;
private final CountDownLatch latch;
private double pi;
private int nrOfResults;
private long start;
private ActorRef router;
public Master(final int nrOfWorkers, int nrOfMessages,
int nrOfElements, CountDownLatch latch) {
this.nrOfMessages = nrOfMessages;
this.nrOfElements = nrOfElements;
this.latch = latch;
//#create-router
router = this.getContext().actorOf(
new Props(Worker.class).withRouter(new RoundRobinRouter(nrOfWorkers)),
"pi");
//#create-router
}
//#master-receive
public void onReceive(Object message) {
//#handle-messages
if (message instanceof Calculate) {
for (int start = 0; start < nrOfMessages; start++) {
router.tell(new Work(start, nrOfElements), getSelf());
}
} else if (message instanceof Result) {
Result result = (Result) message;
pi += result.getValue();
nrOfResults += 1;
if (nrOfResults == nrOfMessages) getContext().stop(getSelf());
} else throw new IllegalArgumentException("Unknown message [" + message + "]");
//#handle-messages
}
//#master-receive
@Override
public void preStart() {
start = System.currentTimeMillis();
}
@Override
public void postStop() {
System.out.println(String.format(
"\n\tPi estimate: \t\t%s\n\tCalculation time: \t%s millis",
pi, (System.currentTimeMillis() - start)));
latch.countDown();
}
public double getPi() {
return pi;
}
//#master
//#actors-and-messages
public void calculate(final int nrOfWorkers,
final int nrOfElements,
final int nrOfMessages)
throws Exception {
// Create an Akka system
final ActorSystem system = ActorSystem.create();
// this latch is only plumbing to know when the calculation is completed
final CountDownLatch latch = new CountDownLatch(1);
// create the master
ActorRef master = system.actorOf(new Props(new UntypedActorFactory() {
public UntypedActor create() {
return new Master(nrOfWorkers, nrOfMessages, nrOfElements, latch);
}
}));
// start the calculation
master.tell(new Calculate());
// wait for master to shut down
latch.await();
// Shut down the system
system.shutdown();
public Duration getDuration() {
return duration;
}
}
//#messages
//#worker
public static class Worker extends UntypedActor {
//#calculatePiFor
private double calculatePiFor(int start, int nrOfElements) {
double acc = 0.0;
for (int i = start * nrOfElements; i <= ((start + 1) * nrOfElements - 1); i++) {
acc += 4.0 * (1 - (i % 2) * 2) / (2 * i + 1);
}
return acc;
}
//#calculatePiFor
public void onReceive(Object message) {
if (message instanceof Work) {
Work work = (Work) message;
double result = calculatePiFor(work.getStart(), work.getNrOfElements());
getSender().tell(new Result(result), getSelf());
} else {
unhandled(message);
}
}
}
//#worker
//#master
public static class Master extends UntypedActor {
private final int nrOfMessages;
private final int nrOfElements;
private double pi;
private int nrOfResults;
private final long start = System.currentTimeMillis();
private final ActorRef listener;
private final ActorRef workerRouter;
public Master(final int nrOfWorkers, int nrOfMessages, int nrOfElements, ActorRef listener) {
this.nrOfMessages = nrOfMessages;
this.nrOfElements = nrOfElements;
this.listener = listener;
//#create-router
workerRouter = this.getContext().actorOf(new Props(Worker.class).withRouter(new RoundRobinRouter(nrOfWorkers)),
"workerRouter");
//#create-router
}
//#master-receive
public void onReceive(Object message) {
//#handle-messages
if (message instanceof Calculate) {
for (int start = 0; start < nrOfMessages; start++) {
workerRouter.tell(new Work(start, nrOfElements), getSelf());
}
} else if (message instanceof Result) {
Result result = (Result) message;
pi += result.getValue();
nrOfResults += 1;
if (nrOfResults == nrOfMessages) {
// Send the result to the listener
Duration duration = Duration.create(System.currentTimeMillis() - start, TimeUnit.MILLISECONDS);
listener.tell(new PiApproximation(pi, duration), getSelf());
// Stops this actor and all its supervised children
getContext().stop(getSelf());
}
} else {
unhandled(message);
}
//#handle-messages
}
//#master-receive
}
//#master
//#result-listener
public static class Listener extends UntypedActor {
public void onReceive(Object message) {
if (message instanceof PiApproximation) {
PiApproximation approximation = (PiApproximation) message;
System.out.println(String.format("\n\tPi approximation: \t\t%s\n\tCalculation time: \t%s",
approximation.getPi(), approximation.getDuration()));
getContext().system().shutdown();
} else {
unhandled(message);
}
}
}
//#result-listener
//#actors-and-messages
public void calculate(final int nrOfWorkers, final int nrOfElements, final int nrOfMessages) {
// Create an Akka system
ActorSystem system = ActorSystem.create("PiSystem");
// create the result listener, which will print the result and shutdown the system
final ActorRef listener = system.actorOf(new Props(Listener.class));
// create the master
ActorRef master = system.actorOf(new Props(new UntypedActorFactory() {
public UntypedActor create() {
return new Master(nrOfWorkers, nrOfMessages, nrOfElements, listener);
}
}), "master");
// start the calculation
master.tell(new Calculate());
}
}
//#app

View file

@ -5,7 +5,7 @@ package akka.tutorial.first.scala
//#imports
import akka.actor._
import akka.routing._
import akka.routing.RoundRobinRouter
import akka.util.Duration
import akka.util.duration._
//#imports
@ -21,7 +21,7 @@ object Pi extends App {
case object Calculate extends PiMessage
case class Work(start: Int, nrOfElements: Int) extends PiMessage
case class Result(value: Double) extends PiMessage
case class PiEstimate(pi: Double, duration: Duration)
case class PiApproximation(pi: Double, duration: Duration)
//#messages
//#worker
@ -52,21 +52,21 @@ object Pi extends App {
val start: Long = System.currentTimeMillis
//#create-router
val router = context.actorOf(
Props[Worker].withRouter(RoundRobinRouter(nrOfWorkers)), name = "workers")
val workerRouter = context.actorOf(
Props[Worker].withRouter(RoundRobinRouter(nrOfWorkers)), name = "workerRouter")
//#create-router
//#master-receive
def receive = {
//#handle-messages
case Calculate
for (i 0 until nrOfMessages) router ! Work(i * nrOfElements, nrOfElements)
for (i 0 until nrOfMessages) workerRouter ! Work(i * nrOfElements, nrOfElements)
case Result(value)
pi += value
nrOfResults += 1
if (nrOfResults == nrOfMessages) {
// Send the result to the listener
listener ! PiEstimate(pi, duration = (System.currentTimeMillis - start).millis)
listener ! PiApproximation(pi, duration = (System.currentTimeMillis - start).millis)
// Stops this actor and all its supervised children
context.stop(self)
}
@ -80,8 +80,8 @@ object Pi extends App {
//#result-listener
class Listener extends Actor {
def receive = {
case PiEstimate(pi, duration)
println("\n\tPi estimate: \t\t%s\n\tCalculation time: \t%s"
case PiApproximation(pi, duration)
println("\n\tPi approximation: \t\t%s\n\tCalculation time: \t%s"
.format(pi, duration))
context.system.shutdown()
}