How to avoid a thread stealing the turn of another thread?

[Nafai]

Let's have an example (just a generic program with threads and a monitor)


class MyMonitor {
....
public synchronized void m()
{
...
while(...) wait(); // (A)
...
notifyAll();
}

};

class MyThread implements Runnable {
....
MyMonitor m;
MyThread(MyMonitor m) { this.m=m;}
public void run()
{
while(true){
...
sleep(...);
// A thread can get monitor here even if there
// are threads waiting (but already notified) in (A)
m();

...
}
}

}

class MainProgram {
public static void main(String[] argv)
{
MyMonitor m = new MyMonitor();
MyThread t1 = new MyThread(m);
MyThread t2 = new MyThread(m);
t1.start();
t2.start();

}


How can I avoid that a thread (which is about to get into the monitor)
steals the turn of the monitor of a thread which has been waiting but
has been notified?

Thanks.

 

[Mark Thornton]

How can I avoid that a thread (which is about to get into the monitor)
steals the turn of the monitor of a thread which has been waiting but
has been notified?

Have a look at the classes in java.util.concurrent. Some of these accept
a fairness parameter which will then ensure first in first out ordering
of threads.

Mark Thornton

 

[Reply7471859353]

An alternative for java.util.concurrent is a high level CSP/Timed-CSP
approach for verifiable multiple parallel process designs.

http://www.cs.ukc.ac.uk/projects/ofa/jcsp/
http://www.quickstone.com/xcsp/jcspnetworkedition/

You may review some of my other Java links at,
http://mywebpage.netscape.com/mawcowboy/links2.htm
http://mywebpage.netscape.com/mawcowboy/goodies1.htm

maw