public abstract class EntityRef<M> extends java.lang.Object implements RecipientRef<M>
EntityRef is NOT an
ActorRef–by design–in order to be explicit about the fact that the life-cycle
of a sharded Entity is very different than a plain Actors. Most notably, this is shown by features of Entities
such as re-balancing (an active Entity to a different node) or passivation. Both of which are aimed to be completely
transparent to users of such Entity. In other words, if this were to be a plain ActorRef, it would be possible to
apply DeathWatch to it, which in turn would then trigger when the sharded Actor stopped, breaking the illusion that
Entity refs are "always there". Please note that while not encouraged, it is possible to expose an Actor's
ActorRef and watch it in case such notification is desired.
Not for user extension.
|Constructor and Description|
|Modifier and Type||Method and Description|
Allows to "ask" the
Send a message to the entity referenced by this EntityRef using *at-most-once* messaging semantics.
public abstract <U> java.util.concurrent.CompletionStage<U> ask(Function<ActorRef<U>,M> message, Timeout timeout)
EntityReffor a reply. See
AskPatternfor a complete write-up of this pattern
Note that if you are inside of an actor you should prefer
as that provides better safety.