Package org.apache.pekko.actor

Interface ActorContext

All Superinterfaces:

ActorRefFactory, ClassicActorContextProvider

All Known Subinterfaces:

AbstractActor.ActorContext

public interface ActorContext
extends ActorRefFactory, ClassicActorContextProvider

The actor context - the view of the actor cell from the actor. Exposes contextual information for the actor and the current message.

There are several possibilities for creating actors (see pekko.actor.Props for details on props):

 // Java or Scala
 context.actorOf(props, "name")
 context.actorOf(props)

 // Scala
 context.actorOf(Props[MyActor])
 context.actorOf(Props(classOf[MyActor], arg1, arg2), "name")

 // Java
 getContext().actorOf(Props.create(MyActor.class));
 getContext().actorOf(Props.create(MyActor.class, arg1, arg2), "name");
 

Where no name is given explicitly, one will be automatically generated.

Method Summary

Modifier and Type	Method	Description
void	become(scala.PartialFunction<Object,scala.runtime.BoxedUnit> behavior)	Changes the Actor's behavior to become the new 'Receive' (PartialFunction[Any, Unit]) handler.
void	become(scala.PartialFunction<Object,scala.runtime.BoxedUnit> behavior, boolean discardOld)	Changes the Actor's behavior to become the new 'Receive' (PartialFunction[Any, Unit]) handler.
scala.Option<ActorRef>	child(String name)	Get the child with the given name if it exists.
scala.collection.immutable.Iterable<ActorRef>	children()	Returns all supervised children; this method returns a view (i.e.
scala.concurrent.ExecutionContextExecutor	dispatcher()	Returns the dispatcher (MessageDispatcher) that is used for this Actor.
ActorRef	parent()	Returns the supervising parent ActorRef.
Props	props()	Retrieve the Props which were used to create this actor.
scala.concurrent.duration.Duration	receiveTimeout()	Gets the current receive timeout.
ActorRef	self()	The ActorRef representing this actor
ActorRef	sender()	Returns the sender 'ActorRef' of the current message.
void	setReceiveTimeout(scala.concurrent.duration.Duration timeout)	Defines the inactivity timeout after which the sending of a pekko.actor.ReceiveTimeout message is triggered.
ActorSystem	system()	The system that the actor belongs to.
void	unbecome()	Reverts the Actor behavior to the previous one on the behavior stack.
ActorRef	unwatch(ActorRef subject)	Unregisters this actor as Monitor for the provided ActorRef.
ActorRef	watch(ActorRef subject)	Registers this actor as a Monitor for the provided ActorRef.
ActorRef	watchWith(ActorRef subject, Object msg)	Registers this actor as a Monitor for the provided ActorRef.
void	writeObject(ObjectOutputStream o)	ActorContexts shouldn't be Serializable

Methods inherited from interface org.apache.pekko.actor.ActorRefFactory

actorOf, actorOf, actorSelection, actorSelection, guardian, lookupRoot, provider, stop, systemImpl

Methods inherited from interface org.apache.pekko.actor.ClassicActorContextProvider

classicActorContext

Method Details

become

void become(scala.PartialFunction<Object,scala.runtime.BoxedUnit> behavior)

Changes the Actor's behavior to become the new 'Receive' (PartialFunction[Any, Unit]) handler. Replaces the current behavior on the top of the behavior stack.

*Warning*: This method is not thread-safe and must not be accessed from threads other than the ordinary actor message processing thread, such as CompletionStage and Future callbacks.

become

void become(scala.PartialFunction<Object,scala.runtime.BoxedUnit> behavior,
 boolean discardOld)

Changes the Actor's behavior to become the new 'Receive' (PartialFunction[Any, Unit]) handler. This method acts upon the behavior stack as follows:

- if discardOld = true it will replace the top element (i.e. the current behavior) - if discardOld = false it will keep the current behavior and push the given one atop

The default of replacing the current behavior on the stack has been chosen to avoid memory leaks in case client code is written without consulting this documentation first (i.e. always pushing new behaviors and never issuing an unbecome())

*Warning*: This method is not thread-safe and must not be accessed from threads other than the ordinary actor message processing thread, such as CompletionStage and Future callbacks.

child

scala.Option<ActorRef> child(String name)

Get the child with the given name if it exists.

*Warning*: This method is not thread-safe and must not be accessed from threads other than the ordinary actor message processing thread, such as CompletionStage and Future callbacks.

children

scala.collection.immutable.Iterable<ActorRef> children()

Returns all supervised children; this method returns a view (i.e. a lazy collection) onto the internal collection of children. Targeted lookups should be using child instead for performance reasons:

 val badLookup = context.children find (_.path.name == "kid")
 // should better be expressed as:
 val goodLookup = context.child("kid")
 

*Warning*: This method is not thread-safe and must not be accessed from threads other than the ordinary actor message processing thread, such as CompletionStage and Future callbacks.

dispatcher

scala.concurrent.ExecutionContextExecutor dispatcher()

Returns the dispatcher (MessageDispatcher) that is used for this Actor. Importing this member will place an implicit ExecutionContext in scope.

This method is thread-safe and can be called from other threads than the ordinary actor message processing thread, such as CompletionStage and Future callbacks.

Specified by:

dispatcher in interface ActorRefFactory

parent

ActorRef parent()

Returns the supervising parent ActorRef.

This method is thread-safe and can be called from other threads than the ordinary actor message processing thread, such as CompletionStage and Future callbacks.

props

Props props()

Retrieve the Props which were used to create this actor.

This method is thread-safe and can be called from other threads than the ordinary actor message processing thread, such as CompletionStage and Future callbacks.

receiveTimeout

scala.concurrent.duration.Duration receiveTimeout()

Gets the current receive timeout. When specified, the receive method should be able to handle a pekko.actor.ReceiveTimeout message.

*Warning*: This method is not thread-safe and must not be accessed from threads other than the ordinary actor message processing thread, such as CompletionStage and Future callbacks.

self

ActorRef self()

The ActorRef representing this actor

This method is thread-safe and can be called from other threads than the ordinary actor message processing thread, such as CompletionStage and Future callbacks.

sender

ActorRef sender()

Returns the sender 'ActorRef' of the current message.

*Warning*: This method is not thread-safe and must not be accessed from threads other than the ordinary actor message processing thread, such as CompletionStage and Future callbacks.

setReceiveTimeout

void setReceiveTimeout(scala.concurrent.duration.Duration timeout)

Defines the inactivity timeout after which the sending of a pekko.actor.ReceiveTimeout message is triggered. When specified, the receive function should be able to handle a pekko.actor.ReceiveTimeout message. 1 millisecond is the minimum supported timeout.

Please note that the receive timeout might fire and enqueue the ReceiveTimeout message right after another message was enqueued; hence it is '''not guaranteed''' that upon reception of the receive timeout there must have been an idle period beforehand as configured via this method.

Once set, the receive timeout stays in effect (i.e. continues firing repeatedly after inactivity periods). Pass in Duration.Undefined to switch off this feature.

Messages marked with NotInfluenceReceiveTimeout will not reset the timer. This can be useful when ReceiveTimeout should be fired by external inactivity but not influenced by internal activity, e.g. scheduled tick messages.

*Warning*: This method is not thread-safe and must not be accessed from threads other than the ordinary actor message processing thread, such as CompletionStage and Future callbacks.

system

ActorSystem system()

The system that the actor belongs to. Importing this member will place an implicit ActorSystem in scope.

This method is thread-safe and can be called from other threads than the ordinary actor message processing thread, such as CompletionStage and Future callbacks.

unbecome

void unbecome()

Reverts the Actor behavior to the previous one on the behavior stack.

*Warning*: This method is not thread-safe and must not be accessed from threads other than the ordinary actor message processing thread, such as CompletionStage and Future callbacks.

unwatch

ActorRef unwatch(ActorRef subject)

Unregisters this actor as Monitor for the provided ActorRef.

Returns:

the provided ActorRef

*Warning*: This method is not thread-safe and must not be accessed from threads other than the ordinary actor message processing thread, such as CompletionStage and Future callbacks.

watch

ActorRef watch(ActorRef subject)

Registers this actor as a Monitor for the provided ActorRef. This actor will receive a Terminated(subject) message when watched actor is terminated.

watch is idempotent if it is not mixed with watchWith.

It will fail with an IllegalStateException if the same subject was watched before using watchWith. To clear the termination message, unwatch first.

*Warning*: This method is not thread-safe and must not be accessed from threads other than the ordinary actor message processing thread, such as CompletionStage and Future callbacks.

Returns:

the provided ActorRef

watchWith

ActorRef watchWith(ActorRef subject,
 Object msg)

Registers this actor as a Monitor for the provided ActorRef. This actor will receive the specified message when watched actor is terminated.

watchWith is idempotent if it is called with the same msg and not mixed with watch.

It will fail with an IllegalStateException if the same subject was watched before using watch or watchWith with another termination message. To change the termination message, unwatch first.

*Warning*: This method is not thread-safe and must not be accessed from threads other than the ordinary actor message processing thread, such as CompletionStage and Future callbacks.

Returns:

the provided ActorRef

writeObject

void writeObject(ObjectOutputStream o)

ActorContexts shouldn't be Serializable