Re: Suspending and resuming JNI thread

On 30 Nov 2006 01:45:54 -0800, ganeshamutha@gmail.com wrote:


Thread methods suspend(), resume() etc are deprecated:
http://java.sun.com/j2se/1.5.0/docs/guide/misc/threadPrimitiveDeprecation.html

At any rate, your native thread cannot be forced to suspend or exit,
it needs to *cooperate* with the controlling thread. The easiest way
is to periodically call a Java method that can wait on a semaphore.

One way is to create a new instance of the following class, to pass to
your native method:

  public class Suspender {
    private boolean cancelled = false;
    private boolean suspended = false;

    public synchronized boolean wait_here() {
      try {
        while (suspended) {
          wait();
        }
      }
      catch (InterruptedException e) {
        cancelled = true;
      }

      return cancelled;
    }

    public synchronized void suspend() {
      suspended = true;
    }

    public synchronized void resume() {
      suspended = false;
      notify();
    }

    public synchronized void cancel() {
      cancelled = true;
      resume();
    }
  }

From the native method, periodically call wait_here(). If the
controlling thread calls suspend(), the native thread will block in
the next call to wait_here(). When the controlling thread calls
resume(), the native thread will continue.

If the controlling thread calls cancel(), wait_here() will return
true, signalling the native method to return.

/gordon

--
[ don't email me support questions or followups ]
g o r d o n + n e w s @ b a l d e r 1 3 . s e