Annotation Interface HandleEvent

@Documented
@Retention(RUNTIME)
@Target({METHOD,CONSTRUCTOR})
@HandleMessage(EVENT)
public @interface HandleEvent

Marks a method or constructor as an event handler for incoming messages of type MessageType.EVENT.

This annotation is used to designate methods that should be invoked when an event message is received. It can be applied to instance methods or constructors. Constructors or static methods may be used for initializing stateful handlers (see Stateful) in response to creation events.

Event handlers typically return void, as event processing is usually side-effect driven and does not produce a result to be returned or published.

Example:

@HandleEvent
void on(UserCreated event) {
    //do something with the event
}

A method with one unqualified Graph<T> subscribes to every durable change of that model graph. Optional Message and Metadata parameters may appear in any order. The complete-change handler is invoked once per affected root and can inspect the complete before-state through Graph.previous(). An explicit payload parameter, association-qualified Graph, or second Graph keeps ordinary handler selection.

See Also:

• HandleMessage
• MessageType.EVENT

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element	Description
Class<?>[]	allowedClasses	Restricts which payload types this handler may be invoked for.
boolean	disabled	If true, disables this handler during discovery.
MissingProtectedDataPolicy	onMissingProtectedData	Determines how the handler responds when referenced protected data is no longer available.

Element Details

onMissingProtectedData

MissingProtectedDataPolicy onMissingProtectedData

Determines how the handler responds when referenced protected data is no longer available.

Default:

DEFAULT

disabled

boolean disabled

If true, disables this handler during discovery.

Default:

false

allowedClasses

Class<?>[] allowedClasses

Restricts which payload types this handler may be invoked for.

Default:

{}