public interface Trigger
TaskScheduler.schedule(Runnable, Trigger), 
CronTrigger| Modifier and Type | Method and Description | 
|---|---|
| Date | nextExecutionTime(TriggerContext triggerContext)Determine the next execution time according to the given trigger context. | 
@Nullable Date nextExecutionTime(TriggerContext triggerContext)
triggerContext - context object encapsulating last execution times
 and last completion timenull if the trigger won't fire anymore