/**
* Call to get the next task that is ready to be run. If there are no tasks, or the next task
* still has a remaining delay, this will return {@code null}.
*
* <p>If this is being called in parallel with a {@link #tick(ExecutionHandlerInterface)} call,
* the returned task may already be running. You must check the {@code TaskContainer.running}
* boolean if this condition is important to you.
*
* @param onlyReturnReadyTask {@code false} to return scheduled tasks which may not be ready for
* execution
* @return next ready task, or {@code null} if there are none
*/
protected TaskContainer getNextTask(boolean onlyReturnReadyTask) {
TaskContainer nextScheduledTask = scheduledQueue.peekFirst();
TaskContainer nextExecuteTask = executeQueue.peek();
if (nextExecuteTask != null) {
if (nextScheduledTask != null) {
long scheduleDelay;
long executeDelay;
ClockWrapper.stopForcingUpdate();
try {
scheduleDelay = nextScheduledTask.getDelayInMillis();
executeDelay = nextExecuteTask.getDelayInMillis();
} finally {
ClockWrapper.resumeForcingUpdate();
}
if (scheduleDelay < executeDelay) {
return nextScheduledTask;
} else {
return nextExecuteTask;
}
} else {
return nextExecuteTask;
}
} else if (!onlyReturnReadyTask
|| (nextScheduledTask != null && nextScheduledTask.getDelayInMillis() <= 0)) {
return nextScheduledTask;
} else {
return null;
}
}
@Override
public void runComplete() {
synchronized (scheduledQueue.getModificationLock()) {
ClockWrapper.stopForcingUpdate();
try {
updateNextRunTime();
// almost certainly will be the first item in the queue
int currentIndex = scheduledQueue.indexOf(this);
if (currentIndex < 0) {
// task was removed from queue, do not re-insert
return;
}
long nextDelay = getDelayInMillis();
if (nextDelay < 0) {
nextDelay = 0;
}
int insertionIndex = ListUtils.getInsertionEndIndex(scheduledQueue, nextDelay, true);
scheduledQueue.reposition(currentIndex, insertionIndex);
} finally {
ClockWrapper.resumeForcingUpdate();
}
}
}
/**
* Adds a task to scheduled/recurring queue. This call is more expensive than {@link
* #addImmediateExecute(OneTimeTask)}, but is necessary for any tasks which are either delayed or
* recurring.
*
* @param runnable Task to execute on next {@link #tick(ExceptionHandlerInterface)} call
*/
protected void addScheduled(TaskContainer runnable) {
synchronized (scheduledQueue.getModificationLock()) {
ClockWrapper.stopForcingUpdate();
try {
int insertionIndex = ListUtils.getInsertionEndIndex(scheduledQueue, runnable, true);
scheduledQueue.add(insertionIndex, runnable);
} finally {
ClockWrapper.resumeForcingUpdate();
}
}
notifyQueueUpdate();
}
/**
* Abstract call to get the value the scheduler should use to represent the current time. This can
* be overridden if someone wanted to artificially change the time.
*
* @return current time in milliseconds
*/
protected long nowInMillis() {
return ClockWrapper.getSemiAccurateMillis();
}