Cluster.unsubscribe with class parameter, see #2567

akka-cluster/src/main/scala/akka/cluster/Cluster.scala

@@ -185,10 +185,17 @@ class Cluster(val system: ExtendedActorSystem) extends Extension {
     clusterCore ! InternalClusterAction.Subscribe(subscriber, to)
 
   /**
-   * Unsubscribe to cluster domain events.
+   * Unsubscribe to all cluster domain events.
    */
   def unsubscribe(subscriber: ActorRef): Unit =
-    clusterCore ! InternalClusterAction.Unsubscribe(subscriber)
+    clusterCore ! InternalClusterAction.Unsubscribe(subscriber, None)
+
+  /**
+   * Unsubscribe to a specific type of cluster domain events,
+   * matching previous `subscribe` registration.
+   */
+  def unsubscribe(subscriber: ActorRef, to: Class[_]): Unit =
+    clusterCore ! InternalClusterAction.Unsubscribe(subscriber, Some(to))
 
   /**
    * Publish current (full) state of the cluster to subscribers,

akka-cluster/src/main/scala/akka/cluster/ClusterDaemon.scala

@@ -108,7 +108,7 @@ private[cluster] object InternalClusterAction {
 
   sealed trait SubscriptionMessage
   case class Subscribe(subscriber: ActorRef, to: Class[_]) extends SubscriptionMessage
-  case class Unsubscribe(subscriber: ActorRef) extends SubscriptionMessage
+  case class Unsubscribe(subscriber: ActorRef, to: Option[Class[_]]) extends SubscriptionMessage
   /**
    * @param receiver if `receiver` is defined the event will only be sent to that
    *   actor, otherwise it will be sent to all subscribers via the `eventStream`.

akka-cluster/src/main/scala/akka/cluster/ClusterEvent.scala

@@ -192,7 +192,7 @@ private[cluster] final class ClusterDomainEventPublisher extends Actor with Acto
     case currentStats: CurrentInternalStats   ⇒ publishInternalStats(currentStats)
     case PublishCurrentClusterState(receiver) ⇒ publishCurrentClusterState(receiver)
     case Subscribe(subscriber, to)            ⇒ subscribe(subscriber, to)
-    case Unsubscribe(subscriber)              ⇒ unsubscribe(subscriber)
+    case Unsubscribe(subscriber, to)          ⇒ unsubscribe(subscriber, to)
     case PublishDone                          ⇒ sender ! PublishDone
   }
 
@@ -216,8 +216,10 @@ private[cluster] final class ClusterDomainEventPublisher extends Actor with Acto
     eventStream.subscribe(subscriber, to)
   }
 
-  def unsubscribe(subscriber: ActorRef): Unit =
-    eventStream.unsubscribe(subscriber)
+  def unsubscribe(subscriber: ActorRef, to: Option[Class[_]]): Unit = to match {
+    case None    ⇒ eventStream.unsubscribe(subscriber)
+    case Some(c) ⇒ eventStream.unsubscribe(subscriber, c)
+  }
 
   def publishChanges(oldGossip: Gossip, newGossip: Gossip): Unit = {
     // keep the latestGossip to be sent to new subscribers

akka-cluster/src/test/scala/akka/cluster/ClusterDomainEventPublisherSpec.scala

@@ -54,7 +54,7 @@ class ClusterDomainEventPublisherSpec extends AkkaSpec(ClusterDomainEventPublish
   }
 
   override def afterEach(): Unit = {
-    publisher ! Unsubscribe(testActor)
+    publisher ! Unsubscribe(testActor, None)
     system.stop(publisher)
   }
 
@@ -116,6 +116,12 @@ class ClusterDomainEventPublisherSpec extends AkkaSpec(ClusterDomainEventPublish
       expectMsgType[SeenChanged]
     }
 
+    "support unsubscribe" in {
+      publisher ! Unsubscribe(testActor, Some(classOf[ClusterDomainEvent]))
+      publisher ! PublishChanges(g1, g2)
+      expectNoMsg
+    }
+
   }
 
 }