wait

I have a implemented a listener that notifies if we receive a new file in a particular directory. This is implemented by polling and using a TimerTask. Now the program is so set up that once it receives a new file it calls another java program that opens the file and validates whether it is the correct file. My problem is that since the polling happens a specified number of seconds later there can arise a case in which a file is being copied in that directory and hence is locked by windows. This throws an IOException since the other java program that tries to open it for validation cannot (

wait()、notify、notifyAll()的使用 参考： https://www.jianshu.com/p/25e243850bd2?appinstall=0 一）.java 中对象锁的模型 JVM会为一个使用内部锁（synchronized）的对象维护两个集合，Entry Set和Wait Set，即锁池和等待池。 二）.Entry Set:* 如果线程A已经持有了对象锁，此时如果有其他线程也想获得该对象锁的话，它只能进入Entry Set，并且处于线程的BLOCKED状态。 可能进入Entey Set的线程： 1).两个抢夺cpu的线程未抢夺到的一方。 2).notify()/notifyAll()唤醒却未抢夺到cpu的线程。 三）.Wait Set: 如果线程A调用了wait()方法，那么线程A会释放该对象的锁，进入到Wait Set，并且处于线程的WAITING状态。 可能进入wait状态的线程： 1）.调用wait()方法。 四）.Runnable状态的转变 Entry Set中的线程的状态为Blocked状态： 1）.当对象锁被释放的时候，JVM会唤醒处于Entry Set中的某一个线程，这个线程 的状态就从BLOCKED转变为RUNNABLE。 Wait Set中的线程状态为Waiting状态： 1) .当对象的notify()方法被调用时

I want to make the program wait for a button to be pressed before it continues, I tried creating a while loop and having it loop until the button is clicked and sets a bool to true for the while loop to end, this made it crash while (!Redpress) { //I'd like the wait here } Redpress = false; It doesn't matter whether or not the while is there, as long as the program waits for the button press before setting "Redpress" to false... Any Ideas? Use events - it's what they're designed for. You don't need to use a boolean variable for this in the Button_Click event handler call your code: private

i am developing one application in blackberry java development. I am requesting to http means i am connecting to web service .response of web service taking some time .That time i want to display some waiting screen. Could you tell me how can i do that.... Regards Pankaj Pareek Basically you need to start the network request in a background thread. Once the network operation is complete you should notify the main/UI thread to change the waiting screen into the results. To notify the main thread have a look at the link below and search for invokeLater : http://developers.sun.com/mobility/midp

I have this: def get_process(): pids = [] process = None for i in os.listdir('/proc'): if i.isdigit(): pids.append(i) for pid in pids: proc = open(os.path.join('/proc', pid, 'cmdline'), 'r').readline() if proc == "Something": process = pid return process def is_running(pid): return os.path.exists("/proc/%s" % str(pid)) Then i do this: process = get_process() if process == None: #do something else: #Wait until the process end while is_running(process): pass I think this is not the best way to wait for the process to terminate, there must be some function wait or something, but i can't find it.

In this case, say I wanted to wait on a condition to happen, that may happen at any random time. while True: if condition: #Do Whatever else: pass As you can see, pass will just happen until the condition is True. But while the condition isn't True the cpu is being pegged with pass causing higher cpu usage, when I simply just want it to wait until the condition occurs. How may I do this? See Busy_loop#Busy-waiting_alternatives : Most operating systems and threading libraries provide a variety of system calls that will block the process on an event, such as lock acquisition, timer changes, I/O

I'll make this short: Is there a way / library in Wicket to show an activity indicator? You know, the spinning thing that moves while the user is waiting for something, or is it just a javascript thing? Thanks for your help. If this is an ajax operation then you can look at the implementations of IAjaxIndicatorAware . These implementations will show a 'spinner' while the operation is processing. e.g. IndicatingAjaxButton and IndicatingAjaxLink You could also look at AjaxIndicatorAppender and alter it your own needs for non ajax things ? Check here to generate your own 'activity indicator'.

I am using Boost MSM (basic and functor front-ends) and am trying to implement the following state machine: In words: Enter state State1 Enter state A and execute action_A. After 2 seconds, print "Trying again..." and re-execute state A (i.e. call its entry action). This loops forever... At the same time as 2 (i.e. "in parallel"), enter state B and execute action_B. After 5 seconds, print "Trying again..." and re-execute state B (i.e. call its entry action). This loops forever... I would like to know the way to create this state machine in Boost MSM. There are two tricks here which I cannot