General exceptions for Spring's scheduling support,
independent of any specific scheduling system.
||Extension of the Runnable interface, adding special callbacks
for long-running operations.
TaskExecutor extension exposing
scheduling characteristics that are relevant to potential task submitters.
||Task scheduler interface that abstracts the scheduling of
Runnable Runnables based on different kinds of triggers.
||Common interface for trigger objects that determine the next execution time
of a task that they get associated with.
||Context object encapsulating last execution times and last completion time
of a given task.
||General exception to be thrown on scheduling failures,
such as the scheduler already having shut down.