Can be overridden to intercept calls to postRestart
.
Can be overridden to intercept calls to postStop
.
Can be overridden to intercept calls to preRestart
.
Can be overridden to intercept calls to preStart
.
INTERNAL API.
Stores the context for this actor, including self, and sender.
Stores the context for this actor, including self, and sender.
It is implicit to support operations such as forward
.
WARNING: Only valid within the Actor itself, so do not close over it and publish it to other threads!
akka.actor.ActorContext is the Scala API. getContext
returns a
akka.actor.UntypedActorContext, which is the Java API of the actor
context.
Gossip to peer nodes.
User overridable callback: By default it calls preStart()
.
User overridable callback: By default it calls preStart()
.
the Throwable that caused the restart to happen
Is called right AFTER restart on the newly created Actor to allow reinitialization after an Actor crash.
User overridable callback.
User overridable callback.
Is called asynchronously after 'actor.stop()' is invoked. Empty default implementation.
User overridable callback: By default it disposes of all children and then calls postStop()
.
User overridable callback: By default it disposes of all children and then calls postStop()
.
the Throwable that caused the restart to happen
optionally the current message the actor processed when failing, if applicable
Is called on a crashed Actor right BEFORE it is restarted to allow clean up of resources before Actor is terminated.
User overridable callback.
User overridable callback.
Is called when an Actor is started. Actors are automatically started asynchronously when created. Empty default implementation.
This defines the initial actor behavior, it must return a partial function with the actor logic.
This defines the initial actor behavior, it must return a partial function with the actor logic.
The 'self' field holds the ActorRef for this actor.
The 'self' field holds the ActorRef for this actor.
Can be used to send messages to itself:
self ! message
The reference sender Actor of the last received message.
The reference sender Actor of the last received message.
Is defined if the message was sent from another Actor,
else deadLetters
in akka.actor.ActorSystem.
WARNING: Only valid within the Actor itself, so do not close over it and publish it to other threads!
User overridable definition the strategy to use for supervising child actors.
User overridable definition the strategy to use for supervising child actors.
User overridable callback.
User overridable callback.
Is called when a message isn't handled by the current behavior of the actor by default it fails with either a akka.actor.DeathPactException (in case of an unhandled akka.actor.Terminated message) or publishes an akka.actor.UnhandledMessage to the actor's system's akka.event.EventStream
This actor manages a registry of actor references and replicates the entries to peer actors among all cluster nodes or a group of nodes tagged with a specific role.
The
DistributedPubSubMediator
is supposed to be started on all nodes, or all nodes with specified role, in the cluster. The mediator can be started with the DistributedPubSubExtension or as an ordinary actor.Changes are only performed in the own part of the registry and those changes are versioned. Deltas are disseminated in a scalable way to other nodes with a gossip protocol. The registry is eventually consistent, i.e. changes are not immediately visible at other nodes, but typically they will be fully replicated to all other nodes after a few seconds.
You can send messages via the mediator on any node to registered actors on any other node. There is three modes of message delivery.
1. DistributedPubSubMediator.Send - The message will be delivered to one recipient with a matching path, if any such exists in the registry. If several entries match the path the message will be sent via the supplied
routingLogic
(default random) to one destination. The sender of the message can specify that local affinity is preferred, i.e. the message is sent to an actor in the same local actor system as the used mediator actor, if any such exists, otherwise route to any other matching entry. A typical usage of this mode is private chat to one other user in an instant messaging application. It can also be used for distributing tasks to registered workers, like a cluster aware router where the routees dynamically can register themselves.2. DistributedPubSubMediator.SendToAll - The message will be delivered to all recipients with a matching path. Actors with the same path, without address information, can be registered on different nodes. On each node there can only be one such actor, since the path is unique within one local actor system. Typical usage of this mode is to broadcast messages to all replicas with the same path, e.g. 3 actors on different nodes that all perform the same actions, for redundancy.
3. DistributedPubSubMediator.Publish - Actors may be registered to a named topic instead of path. This enables many subscribers on each node. The message will be delivered to all subscribers of the topic. For efficiency the message is sent over the wire only once per node (that has a matching topic), and then delivered to all subscribers of the local topic representation. This is the true pub/sub mode. A typical usage of this mode is a chat room in an instant messaging application.
4. DistributedPubSubMediator.Publish with sendOneMessageToEachGroup - Actors may be subscribed to a named topic with an optional property
group
. If subscribing with a group name, each message published to a topic with thesendOneMessageToEachGroup
flag is delivered via the suppliedroutingLogic
(default random) to one actor within each subscribing group. If all the subscribed actors have the same group name, then this works just like DistributedPubSubMediator.Send and all messages are delivered to one subscribe. If all the subscribed actors have different group names, then this works like normal DistributedPubSubMediator.Publish and all messages are broadcast to all subscribers.You register actors to the local mediator with DistributedPubSubMediator.Put or DistributedPubSubMediator.Subscribe.
Put
is used together withSend
andSendToAll
message delivery modes. TheActorRef
inPut
must belong to the same local actor system as the mediator.Subscribe
is used together withPublish
. Actors are automatically removed from the registry when they are terminated, or you can explicitly remove entries with DistributedPubSubMediator.Remove or DistributedPubSubMediator.Unsubscribe.Successful
Subscribe
andUnsubscribe
is acknowledged with DistributedPubSubMediator.SubscribeAck and DistributedPubSubMediator.UnsubscribeAck replies.