/**
* Main execution method for delayed or periodic tasks. If pool is shut down, rejects the task.
* Otherwise adds task to queue and starts a thread, if necessary, to run it. (We cannot prestart
* the thread to run the task because the task (probably) shouldn't be run yet,) If the pool is
* shut down while the task is being added, cancel and remove it if required by state and
* run-after-shutdown parameters.
*
* @param task the task
*/
private void delayedExecute(RunnableScheduledFuture<?> task) {
if (isShutdown()) reject(task);
else {
super.getQueue().add(task);
if (isShutdown() && !canRunInCurrentRunState(task.isPeriodic()) && remove(task))
task.cancel(false);
else ensurePrestart();
}
}
/**
* Cancels and clears the queue of all tasks that should not be run due to shutdown policy.
* Invoked within super.shutdown.
*/
@Override
void onShutdown() {
BlockingQueue<Runnable> q = super.getQueue();
boolean keepDelayed = getExecuteExistingDelayedTasksAfterShutdownPolicy();
boolean keepPeriodic = getContinueExistingPeriodicTasksAfterShutdownPolicy();
if (!keepDelayed && !keepPeriodic) {
for (Object e : q.toArray())
if (e instanceof RunnableScheduledFuture<?>) ((RunnableScheduledFuture<?>) e).cancel(false);
q.clear();
} else {
// Traverse snapshot to avoid iterator exceptions
for (Object e : q.toArray()) {
if (e instanceof RunnableScheduledFuture) {
RunnableScheduledFuture<?> t = (RunnableScheduledFuture<?>) e;
if ((t.isPeriodic() ? !keepPeriodic : !keepDelayed)
|| t.isCancelled()) { // also remove if already cancelled
if (q.remove(t)) t.cancel(false);
}
}
}
}
tryTerminate();
}