问题
Upon an event, I'd like to run a task/runnable but delay it's execution in 2 seconds.
During these 2 seconds, if the same event occurs, I'd like to remove the previous task and re-post it to run - again delayed by 2 seconds.
An example scenario would be background compilation. When a file is saved, I'm waiting 2 seconds and start compiling the class and other, depending classes. I don't want to do it all the time - especially if there are editors that save files automatically, like IntelliJ IDEA.
So, how can I remove/postDelayed runnables in Java, like Android's Handler (remove / postDelayed)?
回答1:
you can use the Executors.newScheduledThreadPool in order to schedule the task,
and you can follow this post's answer :
BlockingQueue<Runnable> queue = threadPool.getQueue();
in order to get the queued runnables.
回答2:
To delay any task and "restart" the delay, you can use Swing timer and if it is running, use its method restart.
回答3:
I suppose you could use the ScheduledExecutor to accomplish this, by adding a mechanism to replace queued tasks with re-queued ones. You could look into the source code of ScheduledThreadPoolExecutor to give an idea, perhaps overriding the implementation of ScheduledFuture<?> schedule( Runnable command, long delay, TimeUnit unit ) and figuring out to avoid the scheduling, only running the tasks once.
Cheers,
来源：https://stackoverflow.com/questions/30074890/how-to-remove-postdelayed-runnables-in-java