Class EventSourcedEntity<S>

Type Parameters:
S - The type of the state for this entity.

public abstract class EventSourcedEntity<S> extends Object
  • Constructor Details

    • EventSourcedEntity

      public EventSourcedEntity()
  • Method Details

    • emptyState

      public S emptyState()
      Implement by returning the initial empty state object. This object will be passed into the command and event handlers, until a new state replaces it.

      Also known as "zero state" or "neutral state".

      The default implementation of this method returns null. It can be overridden to return a more sensible initial state.

    • commandContext

      protected final CommandContext commandContext()
      Additional context and metadata for a command handler.

      It will throw an exception if accessed from constructor or event handler.

    • _internalSetCommandContext

      public void _internalSetCommandContext(Optional<CommandContext> context)
    • eventContext

      protected final EventContext eventContext()
      Additional context and metadata for an event handler.

      It will throw an exception if accessed from constructor or command handler.

    • _internalSetEventContext

      public void _internalSetEventContext(Optional<EventContext> context)
    • _internalSetCurrentState

      public void _internalSetCurrentState(S state)
    • currentState

      @ApiMayChange protected final S currentState()
      Returns the state as currently stored by Kalix.

      Note that modifying the state directly will not update it in storage. To save the state, one must call {effects().updateState()}.

      This method can only be called when handling a command or an event. Calling it outside a method (eg: in the constructor) will raise a IllegalStateException exception.

      IllegalStateException - if accessed outside a handler method
    • effects

      protected final EventSourcedEntity.Effect.Builder<S> effects()