Re: Interrupt a sleeping thread without interrupting I/O

From:
Chris <spam_me_not@goaway.com>
Newsgroups:
comp.lang.java.programmer
Date:
Wed, 09 May 2007 18:56:47 -0500
Message-ID:
<46425f3b$0$5578$9a6e19ea@news.newshosting.com>
Tom Hawtin wrote:

Knute Johnson wrote:

Chris wrote:

I'd like to terminate the thread quickly, but gracefully. If it's
sleeping, I'd like to wake it up and have it exit; if it's reading
data, I want it to finish and then terminate.


How would you implement that with wait/notify?


In the I/O thread:

    for (;;) {
        performIO();
        synchronized (lock) {
            if (exit) {
                return;
            }

            lock.wait(delay);

            if (exit) {
                return;
            }
        }
    }

In interrupting thread:

    public void stopIOThread() {
        synchronized (lock) {
            exit = true;
            lock.notifyAll();
        }
    }

Tom Hawtin


I'm confused. Suppose I/O thread is currently waiting, sitting in the
synchronized{} block. The interrupting thread tries to call
stopIOThread(). Wouldn't it just hang, waiting to get into the
synchronized{} block? It would never get a chance to call notifyAll()
until I/O thread had timed out.

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