Package org.apache.pekko.actor.typed.receptionist

Interface Receptionist.Listing

All Known Implementing Classes:

ReceptionistMessages.Listing

Enclosing class:

Receptionist

public static interface Receptionist.Listing

Current listing of all Actors that implement the protocol given by the ServiceKey.

You can use key.Listing for type-safe pattern matching.

Not for user extension.

Method Summary

Modifier and Type	Method	Description
<T> scala.collection.immutable.Set<ActorRef<T>>	allServiceInstances(ServiceKey<T> key)	Scala API: Return both the reachable and the unreachable service instances.
<T> Set<ActorRef<T>>	getAllServiceInstances(ServiceKey<T> key)	Java API: Return both the reachable and the unreachable service instances.
ServiceKey<?>	getKey()	Java API
<T> Set<ActorRef<T>>	getServiceInstances(ServiceKey<T> key)	Java API: Return the reachable service instances.
boolean	isForKey(ServiceKey<?> key)
ServiceKey<?>	key()	Scala API
<T> scala.collection.immutable.Set<ActorRef<T>>	serviceInstances(ServiceKey<T> key)	Scala API: Return the reachable service instances.
boolean	servicesWereAddedOrRemoved()	Returns true only if this Listing was sent triggered by new actors added or removed to the receptionist.

Method Details

key

ServiceKey<?> key()

Scala API

getKey

ServiceKey<?> getKey()

Java API

isForKey

boolean isForKey(ServiceKey<?> key)

serviceInstances

<T> scala.collection.immutable.Set<ActorRef<T>> serviceInstances(ServiceKey<T> key)

Scala API: Return the reachable service instances.

In a non-clustered ActorSystem this will always be all registered instances for a service key.

For a clustered ActorSystem it only contain services on nodes that are not seen as unreachable (note that they could have still have become unreachable between this message being sent and the receiving actor processing it).

For a list including both reachable and unreachable instances see allServiceInstances(org.apache.pekko.actor.typed.receptionist.ServiceKey<T>)

Also, see ServiceKey.Listing for more convenient pattern matching

getServiceInstances

<T> Set<ActorRef<T>> getServiceInstances(ServiceKey<T> key)

Java API: Return the reachable service instances.

In a non-clustered ActorSystem this will always be all registered instances for a service key.

For a clustered ActorSystem it only contain services on nodes that has are not seen as unreachable (note that they could have still have become unreachable between this message being sent and the receiving actor processing it).

For a list including both reachable and unreachable instances see getAllServiceInstances(org.apache.pekko.actor.typed.receptionist.ServiceKey<T>)

allServiceInstances

<T> scala.collection.immutable.Set<ActorRef<T>> allServiceInstances(ServiceKey<T> key)

Scala API: Return both the reachable and the unreachable service instances.

In a non-clustered ActorSystem this will always be the same as serviceInstances(org.apache.pekko.actor.typed.receptionist.ServiceKey<T>).

For a clustered ActorSystem this include both services on nodes that are reachable and nodes that are unreachable.

getAllServiceInstances

<T> Set<ActorRef<T>> getAllServiceInstances(ServiceKey<T> key)

Java API: Return both the reachable and the unreachable service instances.

In a non-clustered ActorSystem this will always be the same as getServiceInstances(org.apache.pekko.actor.typed.receptionist.ServiceKey<T>).

For a clustered ActorSystem this include both services on nodes that are reachable and nodes that are unreachable.

servicesWereAddedOrRemoved

boolean servicesWereAddedOrRemoved()

Returns true only if this Listing was sent triggered by new actors added or removed to the receptionist. When false the event is only about reachability changes - meaning that the full set of actors (allServiceInstances(org.apache.pekko.actor.typed.receptionist.ServiceKey<T>) or getAllServiceInstances(org.apache.pekko.actor.typed.receptionist.ServiceKey<T>)) is the same as the previous Listing.

knowing this is useful for subscribers only concerned with allServiceInstances(org.apache.pekko.actor.typed.receptionist.ServiceKey<T>) or getAllServiceInstances(org.apache.pekko.actor.typed.receptionist.ServiceKey<T>) that can then ignore Listings related to reachability.

In a non-clustered ActorSystem this will be true for all listings. For Find queries and the initial listing for a Subscribe this will always be true.