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import scala.actors._
import scala.concurrent.duration._
import scala.concurrent.{ Promise, Await }
import scala.actors.Actor._
/* PinS, Listing 32.1: A simple actor
*/
object SillyActor extends Actor {
def act() {
for (i <- 1 to 5)
println("I'm acting!")
println("Post stop")
}
}
object SeriousActor extends Actor {
def act() {
for (i <- 1 to 5)
println("To be or not to be.")
}
}
/* PinS, Listing 32.3: An actor that calls react
*/
object NameResolver extends Actor {
import java.net.{InetAddress, UnknownHostException}
def act() {
react {
case (name: String, actor: Actor) =>
actor ! getIp(name)
act()
case "EXIT" =>
println("Name resolver exiting.")
// quit
case msg =>
println("Unhandled message: " + msg)
act()
}
}
def getIp(name: String): Option[InetAddress] = {
try {
Some(InetAddress.getByName(name))
} catch {
case _: UnknownHostException => None
}
}
}
object Test extends App {
/* PinS, Listing 32.2: An actor that calls receive
*/
def makeEchoActor(): Actor = actor {
while (true) {
receive {
case 'stop =>
exit()
case msg =>
println("received message: " + msg)
}
}
}
/* PinS, page 696
*/
def makeIntActor(): Actor = actor {
receive {
case x: Int => // I only want Ints
println("Got an Int: " + x)
}
}
actor {
self.trapExit = true
self.link(SillyActor)
SillyActor.start()
react {
case Exit(SillyActor, _) =>
self.link(SeriousActor)
SeriousActor.start()
react {
case Exit(SeriousActor, _) =>
val seriousPromise2 = Promise[Boolean]
// PinS, page 694
val seriousActor2 = actor {
for (i <- 1 to 5)
println("That is the question.")
seriousPromise2.success(true)
}
Await.ready(seriousPromise2.future, 5 seconds)
val echoActor = makeEchoActor()
self.link(echoActor)
echoActor ! "hi there"
echoActor ! 15
echoActor ! 'stop
react {
case Exit(_, _) =>
val intActor = makeIntActor()
intActor ! "hello"
intActor ! math.Pi
// only the following send leads to output
intActor ! 12
}
}
}
}
}
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