// =============================================
// 1. Import statements and Server messages
import scala.actors._
import scala.actors.Actor._
import scala.actors.behavior._
import scala.actors.behavior.Helpers._
sealed abstract class SampleMessage
case object Ping extends SampleMessage
case object Pong extends SampleMessage
case object OneWay extends SampleMessage
case object Die extends SampleMessage
// =============================================
// 2. Create the GenericServer by extending the GenericServer trait and override the 'body' method
class SampleServer extends GenericServer {
// This method implements the core server logic and naturally has to be overridden
override def body: PartialFunction[Any, Unit] = {
case Ping =>
println("Received Ping"); reply(Pong)
case OneWay =>
println("Received OneWay")
case Die =>
println("Received Die..dying...")
throw new RuntimeException("Received Die message")
}
// GenericServer also has some callback life-cycle methods, such as init(..) and shutdown(..)
}
// =============================================
// 3. Wrap our SampleServer in a GenericServerContainer and give it a name to be able to refer to it later.
object sampleServer1 extends GenericServerContainer("sample1", () => new SampleServer)
object sampleServer2 extends GenericServerContainer("sample2", () => new SampleServer)
// =============================================
// 4. Create a Supervisor configuration (and a SupervisorFactory) that is configuring our SampleServer (takes a list of 'Worker' configurations, one or many)
object factory extends SupervisorFactory {
override protected def getSupervisorConfig: SupervisorConfig = {
SupervisorConfig(
RestartStrategy(AllForOne, 3, 10000),
Worker(
sampleServer1,
LifeCycle(Permanent, 1000)) ::
Worker(
sampleServer2,
LifeCycle(Permanent, 1000)) ::
Nil)
}
}
// =============================================
// 5. Create a new Supervisor with the custom factory
val supervisor = factory.newSupervisor
// =============================================
// 6. Start the Supervisor (which starts the server(s))
supervisor ! Start
// =============================================
// 7. Try to send a one way asyncronous message to our servers
sampleServer1 ! OneWay
// Try to get sampleServer2 from the Supervisor before sending a message
supervisor.getServer("sample2") match {
case Some(server2) => server2 ! OneWay
case None => println("server [sample2] could not be found")
}
// =============================================
// 8. Try to send an asyncronous message - receive a future - wait 100 ms (time-out) for the reply
val future = sampleServer1 !! Ping
val reply1 = future.receiveWithin(100) match {
case Some(reply) =>
println("Received reply: " + reply)
case None =>
println("Did not get a reply witin 100 ms")
}
// =============================================
// 9. Try to send a message (Die) telling the server to kill itself (throw an exception)
sampleServer1 ! Die
// =============================================
// 10. Send an asyncronous message and wait on a future. If it times out -> use error handler (in this case throw an exception). It is likely that this call will time out since the server is in the middle of recovering from failure.
val reply2 = try {
sampleServer1 !!! (Ping, throw new RuntimeException("Time-out"), 10) // time out is set to 10 ms (very low on purpose)
} catch { case e => println("Expected exception: " + e.toString); Pong }
// =============================================
// 11. Server should be up again. Try the same call again
val reply3 = try {
sampleServer1 !!! (Ping, throw new RuntimeException("Time-out"), 1000)
} catch { case e => println("Expected exception: " + e.toString); Pong }
// Also check server number 2
sampleServer2 ! Ping
// =============================================
// 11. Try to hotswap the server implementation
sampleServer1.hotswap(Some({
case Ping =>
println("Hotswapped Ping")
}))
// =============================================
// 12. Try the hotswapped server out
sampleServer1 ! Ping
// =============================================
// 13. Hotswap again
sampleServer1.hotswap(Some({
case Pong =>
println("Hotswapped again, now doing Pong")
reply(Ping)
}))
// =============================================
// 14. Send an asyncronous message that will wait on a future. Method returns an Option[T] => if Some(result) -> return result, if None -> print out an info message (or throw an exception or do whatever you like...)
val reply4 = (sampleServer1 !!! Pong).getOrElse({println("Time out when sending Pong"); Ping})
// Same invocation with pattern matching syntax.
val reply5 = sampleServer1 !!! Pong match {
case Some(result) => result
case None => println("Time out when sending Pong"); Ping
}
// =============================================
// 15. Hotswap back to original implementation by passing in None
sampleServer1.hotswap(None)
// =============================================
// 16. Test the final hotswap by sending an async message
sampleServer1 ! Ping
// =============================================
// 17. Shut down the supervisor and its server(s)
supervisor ! Stop
