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| import akka.actor.Actor
import akka.actor.ActorRef
import akka.actor.Props
import akka.util.duration._
import scala.actors.threadpool.TimeUnit
import akka.actor.ActorSystem
sealed trait TableMessage
case class Take(philosopher: ActorRef) extends TableMessage
case class Taken(fork: ActorRef) extends TableMessage
object Eat extends TableMessage
object Think extends TableMessage
object Busy extends TableMessage
object Put extends TableMessage
class Fork extends Actor {
import context.become
def available: Receive = {
case Take(philosopher) =>
become(taken)
philosopher ! Taken(self)
}
def taken: Receive = {
case Take(otherOne) =>
otherOne ! Busy
case Put =>
become(available)
case x => println(x)
}
def receive = available
}
class Philosopher(left: ActorRef, right: ActorRef) extends Actor {
import context.become
import context.system
def hungry: Receive = {
case Taken(this.left) =>
become(waiting_for(right, left))
case Taken(this.right) =>
become(waiting_for(left, right))
case Busy =>
become(denied)
}
def eating: Receive = {
case Think =>
println(self.path.name + " puts down his forks and starts to think")
become(thinking)
left ! Put
right ! Put
system.scheduler.scheduleOnce(3 seconds, self, Eat)
}
def waiting_for(toWaitFor: ActorRef, taken: ActorRef): Receive = {
case Taken(toWaitFor) =>
become(eating)
println(self.path.name + " has taken " + taken.path.name + " and " + toWaitFor.path.name)
system.scheduler.scheduleOnce(3 seconds, self, Think)
case Busy =>
become(thinking)
taken ! Put
self ! Eat
}
def thinking: Receive = {
case Eat =>
become(hungry)
left ! Take(self)
right ! Take(self)
}
def denied: Receive = {
case Taken(fork) =>
become(thinking)
fork ! Put
self ! Eat
case Busy =>
become(thinking)
self ! Eat
}
def receive = {
case Think =>
become(thinking)
system.scheduler.scheduleOnce(1 seconds, self, Eat)
}
}
object Dining extends App {
val system = ActorSystem("DiningTable")
val forks = for (i <- 1 to 5) yield system.actorOf(Props[Fork], "fork" + i)
val philosophers = for {
(name, i) <- (List("Pluto", "Socrates", "Aristotle", "Pythagoras", "Zeno").zipWithIndex)
} yield system.actorOf(Props(new Philosopher(forks(i), forks((i + 1) % 5))), name)
philosophers.foreach(_ ! Think)
}
|