akka.contrib.pattern

DistributedPubSubMediator

class DistributedPubSubMediator extends Actor with ActorLogging

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 the sendOneMessageToEachGroup flag is delivered via the supplied routingLogic (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 with Send and SendToAll message delivery modes. The ActorRef in Put must belong to the same local actor system as the mediator. Subscribe is used together with Publish. 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 and Unsubscribe is acknowledged with DistributedPubSubMediator.SubscribeAck and DistributedPubSubMediator.UnsubscribeAck replies.

Source
DistributedPubSubMediator.scala
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  2. ActorLogging
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Instance Constructors

  1. new DistributedPubSubMediator(role: Option[String], routingLogic: RoutingLogic, gossipInterval: FiniteDuration, removedTimeToLive: FiniteDuration, maxDeltaElements: Int)

Type Members

  1. type Receive = PartialFunction[Any, Unit]

    Definition Classes
    Actor

Value Members

  1. final def !=(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef
  2. final def !=(arg0: Any): Boolean

    Definition Classes
    Any
  3. final def ##(): Int

    Definition Classes
    AnyRef → Any
  4. def +(other: String): String

    Implicit information
    This member is added by an implicit conversion from DistributedPubSubMediator to StringAdd performed by method any2stringadd in scala.Predef.
    Definition Classes
    StringAdd
  5. def ->[B](y: B): (DistributedPubSubMediator, B)

    Implicit information
    This member is added by an implicit conversion from DistributedPubSubMediator to ArrowAssoc[DistributedPubSubMediator] performed by method any2ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @inline()
  6. final def ==(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef
  7. final def ==(arg0: Any): Boolean

    Definition Classes
    Any
  8. def aroundPostRestart(reason: Throwable): Unit

    Can be overridden to intercept calls to postRestart.

    Can be overridden to intercept calls to postRestart. Calls postRestart by default.

    Attributes
    protected[akka]
    Definition Classes
    Actor
  9. def aroundPostStop(): Unit

    Can be overridden to intercept calls to postStop.

    Can be overridden to intercept calls to postStop. Calls postStop by default.

    Attributes
    protected[akka]
    Definition Classes
    Actor
  10. def aroundPreRestart(reason: Throwable, message: Option[Any]): Unit

    Can be overridden to intercept calls to preRestart.

    Can be overridden to intercept calls to preRestart. Calls preRestart by default.

    Attributes
    protected[akka]
    Definition Classes
    Actor
  11. def aroundPreStart(): Unit

    Can be overridden to intercept calls to preStart.

    Can be overridden to intercept calls to preStart. Calls preStart by default.

    Attributes
    protected[akka]
    Definition Classes
    Actor
  12. def aroundReceive(receive: actor.Actor.Receive, msg: Any): Unit

    INTERNAL API.

    INTERNAL API.

    Can be overridden to intercept calls to this actor's current behavior.

    receive

    current behavior.

    msg

    current message.

    Attributes
    protected[akka]
    Definition Classes
    Actor
  13. final def asInstanceOf[T0]: T0

    Definition Classes
    Any
  14. def clone(): AnyRef

    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  15. val cluster: Cluster

  16. def collectDelta(otherVersions: Map[Address, Long]): Iterable[Bucket]

  17. implicit val context: ActorContext

    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.

    Definition Classes
    Actor
  18. def ensuring(cond: (DistributedPubSubMediator) ⇒ Boolean, msg: ⇒ Any): DistributedPubSubMediator

    Implicit information
    This member is added by an implicit conversion from DistributedPubSubMediator to Ensuring[DistributedPubSubMediator] performed by method any2Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  19. def ensuring(cond: (DistributedPubSubMediator) ⇒ Boolean): DistributedPubSubMediator

    Implicit information
    This member is added by an implicit conversion from DistributedPubSubMediator to Ensuring[DistributedPubSubMediator] performed by method any2Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  20. def ensuring(cond: Boolean, msg: ⇒ Any): DistributedPubSubMediator

    Implicit information
    This member is added by an implicit conversion from DistributedPubSubMediator to Ensuring[DistributedPubSubMediator] performed by method any2Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  21. def ensuring(cond: Boolean): DistributedPubSubMediator

    Implicit information
    This member is added by an implicit conversion from DistributedPubSubMediator to Ensuring[DistributedPubSubMediator] performed by method any2Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  22. final def eq(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef
  23. def equals(arg0: Any): Boolean

    Definition Classes
    AnyRef → Any
  24. def finalize(): Unit

    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( classOf[java.lang.Throwable] )
  25. def formatted(fmtstr: String): String

    Implicit information
    This member is added by an implicit conversion from DistributedPubSubMediator to StringFormat performed by method any2stringfmt in scala.Predef.
    Definition Classes
    StringFormat
    Annotations
    @inline()
  26. final def getClass(): Class[_]

    Definition Classes
    AnyRef → Any
  27. def gossip(): Unit

    Gossip to peer nodes.

  28. val gossipTask: Cancellable

  29. def gossipTo(address: Address): Unit

  30. def hashCode(): Int

    Definition Classes
    AnyRef → Any
  31. final def isInstanceOf[T0]: Boolean

    Definition Classes
    Any
  32. def log: LoggingAdapter

    Definition Classes
    ActorLogging
  33. def matchingRole(m: Member): Boolean

  34. def mkKey(path: ActorPath): String

  35. def mkKey(ref: ActorRef): String

  36. def myVersions: Map[Address, Long]

  37. final def ne(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef
  38. val nextVersion: () ⇒ Long

  39. var nodes: Set[Address]

  40. final def notify(): Unit

    Definition Classes
    AnyRef
  41. final def notifyAll(): Unit

    Definition Classes
    AnyRef
  42. def otherHasNewerVersions(otherVersions: Map[Address, Long]): Boolean

  43. def postRestart(reason: Throwable): Unit

    User overridable callback: By default it calls preStart().

    User overridable callback: By default it calls preStart().

    reason

    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.

    Definition Classes
    Actor
    Annotations
    @throws( classOf[Exception] )
  44. def postStop(): Unit

    User overridable callback.

    User overridable callback.

    Is called asynchronously after 'actor.stop()' is invoked. Empty default implementation.

    Definition Classes
    DistributedPubSubMediatorActor
  45. def preRestart(reason: Throwable, message: Option[Any]): Unit

    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().

    reason

    the Throwable that caused the restart to happen

    message

    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.

    Definition Classes
    Actor
    Annotations
    @throws( classOf[Exception] )
  46. def preStart(): Unit

    User overridable callback.

    User overridable callback.

    Is called when an Actor is started. Actors are automatically started asynchronously when created. Empty default implementation.

    Definition Classes
    DistributedPubSubMediatorActor
  47. def prune(): Unit

  48. val pruneInterval: FiniteDuration

  49. val pruneTask: Cancellable

  50. def publish(path: String, msg: Any, allButSelf: Boolean = false): Unit

  51. def publishToEachGroup(path: String, msg: Any): Unit

  52. def put(key: String, valueOption: Option[ActorRef]): Unit

  53. def receive: PartialFunction[Any, Unit]

    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.

    Definition Classes
    DistributedPubSubMediatorActor
  54. def registerTopic(ref: ActorRef): Unit

  55. var registry: Map[Address, Bucket]

  56. val removedTimeToLiveMillis: Long

  57. def selectRandomNode(addresses: IndexedSeq[Address]): Option[Address]

  58. implicit final val self: ActorRef

    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
    

    Definition Classes
    Actor
  59. final def sender(): ActorRef

    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!

    Definition Classes
    Actor
  60. def supervisorStrategy: SupervisorStrategy

    User overridable definition the strategy to use for supervising child actors.

    User overridable definition the strategy to use for supervising child actors.

    Definition Classes
    Actor
  61. final def synchronized[T0](arg0: ⇒ T0): T0

    Definition Classes
    AnyRef
  62. def toString(): String

    Definition Classes
    AnyRef → Any
  63. def unhandled(message: Any): Unit

    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

    Definition Classes
    Actor
  64. final def wait(): Unit

    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  65. final def wait(arg0: Long, arg1: Int): Unit

    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  66. final def wait(arg0: Long): Unit

    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  67. def [B](y: B): (DistributedPubSubMediator, B)

    Implicit information
    This member is added by an implicit conversion from DistributedPubSubMediator to ArrowAssoc[DistributedPubSubMediator] performed by method any2ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc

Shadowed Implicit Value Members

  1. val self: Any

    Implicit information
    This member is added by an implicit conversion from DistributedPubSubMediator to StringAdd performed by method any2stringadd in scala.Predef.
    Shadowing
    This implicitly inherited member is shadowed by one or more members in this class.
    To access this member you can use a type ascription:
    (distributedPubSubMediator: StringAdd).self
    Definition Classes
    StringAdd
  2. val self: Any

    Implicit information
    This member is added by an implicit conversion from DistributedPubSubMediator to StringFormat performed by method any2stringfmt in scala.Predef.
    Shadowing
    This implicitly inherited member is shadowed by one or more members in this class.
    To access this member you can use a type ascription:
    (distributedPubSubMediator: StringFormat).self
    Definition Classes
    StringFormat

Deprecated Value Members

  1. def x: DistributedPubSubMediator

    Implicit information
    This member is added by an implicit conversion from DistributedPubSubMediator to ArrowAssoc[DistributedPubSubMediator] performed by method any2ArrowAssoc in scala.Predef.
    Shadowing
    This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
    To access this member you can use a type ascription:
    (distributedPubSubMediator: ArrowAssoc[DistributedPubSubMediator]).x
    Definition Classes
    ArrowAssoc
    Annotations
    @deprecated
    Deprecated

    (Since version 2.10.0) Use leftOfArrow instead

  2. def x: DistributedPubSubMediator

    Implicit information
    This member is added by an implicit conversion from DistributedPubSubMediator to Ensuring[DistributedPubSubMediator] performed by method any2Ensuring in scala.Predef.
    Shadowing
    This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
    To access this member you can use a type ascription:
    (distributedPubSubMediator: Ensuring[DistributedPubSubMediator]).x
    Definition Classes
    Ensuring
    Annotations
    @deprecated
    Deprecated

    (Since version 2.10.0) Use resultOfEnsuring instead

Inherited from ActorLogging

Inherited from Actor

Inherited from AnyRef

Inherited from Any

Inherited by implicit conversion any2stringadd from DistributedPubSubMediator to StringAdd

Inherited by implicit conversion any2stringfmt from DistributedPubSubMediator to StringFormat

Inherited by implicit conversion any2ArrowAssoc from DistributedPubSubMediator to ArrowAssoc[DistributedPubSubMediator]

Inherited by implicit conversion any2Ensuring from DistributedPubSubMediator to Ensuring[DistributedPubSubMediator]

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