Package kalix.javasdk.action

Class Action

Object

kalix.javasdk.action.Action

public abstract class Action
extends Object

Actions are stateless components that can be used to implement different uses cases, such as:

• a pure function.
• request conversion - you can use Actions to convert incoming data into a different. format before forwarding a call to a different component.
• as a face or controller to fan out to multiple calls to different components.
• publish messages to a Topic.
• subscribe to events from an Event Sourced Entity.
• subscribe to state changes from a Value Entity.
• schedule and cancel Timers.

Actions can be triggered in multiple ways. For example, by:

• a gRPC service call.
• an HTTP service call.
• a forwarded call from another component.
• a scheduled call from a Timer.
• an incoming message from a Topic.
• an incoming event from an Event Sourced Entity, from within the same service or from a different service.
• state changes notification from a Value Entity on the same service.

An Action method should return an Action.Effect that describes what to do next.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	Action.Effect<T>	An Effect is a description of what Kalix needs to do after the command is handled.

Constructor Summary

Constructors

Constructor	Description
Action()

Method Summary

Modifier and Type	Method	Description
void	_internalSetActionContext(Optional<ActionContext> context)	INTERNAL API
protected final ActionContext	actionContext()	Additional context and metadata for a message handler.
protected final ActionContext	contextForComponents()	INTERNAL API
final Action.Effect.Builder	effects()
final TimerScheduler	timers()	Returns a TimerScheduler that can be used to schedule further in time.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

Action

public Action()

Method Details

actionContext

protected final ActionContext actionContext()

Additional context and metadata for a message handler.

It will throw an exception if accessed from constructor.

contextForComponents

protected final ActionContext contextForComponents()

INTERNAL API

Same as actionContext, but if specific error message when accessing components.

_internalSetActionContext

public void _internalSetActionContext(Optional<ActionContext> context)

INTERNAL API

effects

public final Action.Effect.Builder effects()

timers

public final TimerScheduler timers()

Returns a TimerScheduler that can be used to schedule further in time.