Internal classes

These classes are part of Nexus's runtime implementation but are not part of the public API surface. They are tagged @internal in source so they do not appear in the public sidebar of api.nexusactors.com.

Their HTML pages still exist for deep-links; this page lists them so you know they are there and why they are hidden.

Do not depend on these classes directly. If a use case calls for it, file an issue so we can discuss promoting the relevant API to public.

Behavior wrappers (11)

These classes are the concrete sentinels and decorators returned by the public Behavior factory methods. Users call the factories — Behavior::same(), Behavior::receive(), etc. — and hold them as opaque Behavior<T> values. The concrete wrapper type is an implementation detail of ActorCell.

Class	Why internal
EmptyBehavior	Sentinel returned internally before the first behavior is set. Never constructed by users.
SameBehavior	Sentinel returned by Behavior::same(). Users call the factory, never construct directly.
StoppedBehavior	Sentinel returned by Behavior::stopped(). Users call the factory, never construct directly.
UnhandledBehavior	Sentinel returned by Behavior::unhandled(). Routes message to dead letters — implementation detail.
SupervisedBehavior	Wraps a behavior under supervision restart. Created by ActorCell during fault recovery.
SetupBehavior	Lazy-init wrapper returned by Behavior::setup(). Resolved to a concrete behavior on first message.
ReceiveBehavior	Closure-based behavior returned by Behavior::receive(). Holds the handler closure internally.
WithStashBehavior	Behavior decorator that activates the stash buffer. Used by ActorCell internals.
WithStateBehavior	Stateful closure behavior returned by Behavior::withState(). Holds state and handler.
WithTimersBehavior	Behavior decorator that attaches a TimerScheduler. Managed by ActorCell.
UnstashAllBehavior	Sentinel that triggers draining the stash buffer. Internal to stash machinery.

Engine / Runtime (8)

Implementation classes behind public interfaces and factory methods. Users interact with their public interfaces (ActorRef<T>, ActorPath, StashBuffer, etc.) and never construct these directly.

Class	Why internal
ActorCell	Runtime container for one actor's lifecycle and message loop. Implementation detail of ActorSystem::spawn().
DefaultStashBuffer	Default stash buffer implementation. The StashBuffer interface is public; this impl is an internal detail.
DefaultTimerScheduler	Default timer scheduler implementation. Users access timers via ActorContext::scheduleOnce().
LocalActorRef	Concrete ActorRef for in-process actors. Users hold the ActorRef<T> interface, not this class.
DeadLetterRef	Null-object ActorRef for undeliverable messages. Users access via ActorSystem::deadLetters().
FutureRef	Temporary ActorRef created for ask() replies. Created and destroyed per request.
TaskContext	Internal context used during ask() future resolution. Not user-facing.
ActorState	Enum of internal lifecycle states (New, Starting, Running, etc.). A private detail of ActorCell.

Context / Support (4)

Helper types that are shared internally between subsystems but not surfaced to application code.

Class	Why internal
LocalActorPath	Concrete ActorPath for in-process actors. Implementation detail of path creation.
RemoteActorPath	Concrete ActorPath for remote actors. Implementation detail of cluster path parsing.
ActorPathContract	Internal interface shared between LocalActorPath and RemoteActorPath. Not a public API contract.
NullDispatcher	No-op PSR-14 EventDispatcherInterface used when no dispatcher is provided. Internal default.

System messages (6)

Internal control messages sent between ActorCell instances by the framework. These are never sent by user code directly — users send domain messages via tell() or ask(), and the framework manages system messages automatically.

Class	Why internal
Watch	Sent internally to register a death-watch subscription between actors.
Unwatch	Sent internally to cancel a death-watch subscription.
Suspend	Sent internally to pause an actor's message processing (e.g. during supervision).
Resume	Sent internally to resume a suspended actor after supervision completes.
Kill	Sent internally for a forced stop that bypasses graceful shutdown.
SystemMessage	Marker interface for all of the above internal system messages.