Annotation Interface HandleSchedule

@Documented
@Retention(RUNTIME)
@Target({METHOD,CONSTRUCTOR})
@HandleMessage(SCHEDULE)
public @interface HandleSchedule

Marks a method or constructor as a handler for scheduled messages (MessageType.SCHEDULE).

These handlers are invoked in response to scheduled triggers, typically time-based.

Scheduled messages may originate from an explicit schedule call (see MessageScheduler), or from a payload annotated with Periodic, which enables automatic rescheduling after each invocation.

Return behavior

A @HandleSchedule method may return a value to control rescheduling behavior:

• null: continue scheduling using the default strategy if the schedule is Periodic.
• Duration or Instant: overrides the next schedule delay or time.
• A new payload: schedules the returned object as the next scheduled message. If this new payload is annotated with Periodic, the periodic settings on that payload take precedence.
• Returning a new Schedule reschedules that message using the specified payload and deadline.

To cancel a periodic schedule, throw a CancelPeriodic exception.

Example: Dynamic continuation using payload return

@HandleSchedule
PollUpdates on(PollUpdates poll) {
    var updates = Fluxzero.queryAndWait(poll);
    // Process updates
    return new PollUpdates(updates.getContinuationToken());
}

If PollUpdates is annotated with Periodic, its delay or cron expression will be used for rescheduling.

Example: Return a delay for the next schedule

@HandleSchedule
Duration on(HealthCheck ping) {
    if (!isAlive()) {
        throw new CancelPeriodic("Service offline");
    }
    return Duration.ofSeconds(30);
}

This will schedule the same ping message to be retried after 30 seconds.

See Also:

• HandleMessage
• MessageType.SCHEDULE
• Periodic
• MessageScheduler
• CancelPeriodic

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.

Element Details

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:

{}