akka.event.AddressTerminatedTopic.scala Maven / Gradle / Ivy
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/**
* Copyright (C) 2009-2016 Lightbend Inc.
*/
package akka.event
import java.util.concurrent.atomic.AtomicReference
import scala.annotation.tailrec
import akka.actor.ActorRef
import akka.actor.ActorSystem
import akka.actor.AddressTerminated
import akka.actor.ExtendedActorSystem
import akka.actor.Extension
import akka.actor.ExtensionId
import akka.actor.ExtensionIdProvider
/**
* INTERNAL API
*
* Watchers of remote actor references register themselves as subscribers
* of [[akka.actor.AddressTerminated]] notifications. Remote and cluster
* death watch publish `AddressTerminated` when a remote system is deemed
* dead.
*/
private[akka] object AddressTerminatedTopic extends ExtensionId[AddressTerminatedTopic] with ExtensionIdProvider {
override def get(system: ActorSystem): AddressTerminatedTopic = super.get(system)
override def lookup = AddressTerminatedTopic
override def createExtension(system: ExtendedActorSystem): AddressTerminatedTopic =
new AddressTerminatedTopic
}
/**
* INTERNAL API
*/
private[akka] final class AddressTerminatedTopic extends Extension {
private val subscribers = new AtomicReference[Set[ActorRef]](Set.empty[ActorRef])
@tailrec def subscribe(subscriber: ActorRef): Unit = {
val current = subscribers.get
if (!subscribers.compareAndSet(current, current + subscriber))
subscribe(subscriber) // retry
}
@tailrec def unsubscribe(subscriber: ActorRef): Unit = {
val current = subscribers.get
if (!subscribers.compareAndSet(current, current - subscriber))
unsubscribe(subscriber) // retry
}
def publish(msg: AddressTerminated): Unit = {
subscribers.get foreach { _.tell(msg, ActorRef.noSender) }
}
}