Need some help killing threads (not in the way already mentioned..)

Question

I have read the ways in which we should safely kill a thread - and for the most part i understand that. But my question is HOW to implement it in the way that I need.
Basically I have a multithreaded (ewww) app that really is a large job scheduler running 24/7. It can run anywhere from 1 to 15 jobs at a given time. This is fine. What i need is to have the ability to 'kill' a job when I need to. When the app daemon decides its time to run a certain job (based on business logic) it kicks one off, which is a class I made that implements Runnable.
public class SchedulerProcessThread extends SOQBase implements Runnable{}
when its time to start a job i do the usual:
SchedulerProcessThread spt = new SchedulerProcessThread(blah);
Thread t = new Thread(spt, "fooname");
t.start();
Now, this comes to my problem of where/how to kill the job (if needed). A SchedulerProcessThread is linear and finite so it will always have a termination point - it never loops. And when one is kicked off - i do not have a reference to it anymore - I mean, I couldnt if i am constantly running new jobs, potentially hundreds every hour. And jobs can be started in various places in the app, depending upon whether others are already running, etc.
I wish to implement the do-while (alive) logic on the job thread. So in the 'run()' method of my SPT class, I would like the:
while (alive) {
doProcessing();
But how can i invoke a method on my class [SPT] so that it changes the alive var from true to false when i do not have a reference to it?
As a side note, I have a command prompt on the app whereby i can call up all the running 'jobs' which is a list of the running threads under a threadgroup called 'soqjob' (all new Threads that are started with a passing param of and SPT object are under the 'soqjob' threadgroup). So now i can see all those 'soqjob' threads which are currently running Thread objects that have been passed new instances of an SPT class.
Is there anyway i can grab the 'soqjob' thread of my choice and somehow access my SPT class that was originally passed to it in the Thread constructor? if so, then I could pass in the command to stop the do-while loop.
Hmm - does any of this make sense? If i can sum up, the problem is i do not know how to access my own SPT class once I have passed it into a thread object and invoked that thread object's 'start()' method. if i can do that, then i can switch the ALIVE var from true to false and thereby kill the SPT job i need.
Any ideas?
Many thanks
Ian

Answer 1

I would add a Collection (synchronized) to the Scheduler that holds a reference to all the Processes. Pass a reference of the Scheduler to the Processes so that when a Process is done, it can remove itself from the Collection.
public class Scheduler {
     private Collection threads;
     public void addProcess() {
          Runnable runnable = new ProcessThread(this);
          Thread thread = new Thread(runnable);
          thread.start();
          threads.add(thread);
     public void removeProcess(ProcessThread thread) {
          threads.remove(thread);
     private Thread getSelectedThread(Component c) {
          //Find Thread in Collection and return it
     private class Action implements ActionListener {
          public void actionPerformed(ActionEvent e) {
               Thread thread = getSelectedThread(e.getSource());
               thread.interrupt();
class ProcessThread extends ... implements Runnable {
     private Scheduler scheduler;
     public ProcessThread(Scheduler s) {
          this.scheduler = s;
     public void run() {
          while (!Thread.interrupted()) {
               try {
                    doProcessing();
                    Thread.yield();     //Give the other Threads a chance to do some work
               } catch (InterruptedException e) {
                    Thread.currentThread().interrupt();
          this.scheduler.removeProcess(this);     //Remove this Thread from the Scheduler's Collection
}Did you consider using the classes java.util.Timer and java.util.TimerTask?