/*
* Create a thread object using the default constructor ThreadCB() and
* associate this newly created thread with a task (provided as an
* argument to the do create() method).
*
*/
public static ThreadCB do_create(TaskCB task) {
// It is important to keep in mind that each time control is transferred to
// the operating system, it is seen as an opportunity to schedule a thread
// to run. Therefore, regardless of whether the new thread was created
// successfully, the dispatcher must be called (or else a warning will be issued)
// There is a global constant (in IflThreadCB), called MaxThreadsPerTask.
// If this number of threads per task is exceeded, no new thread should be
// created for that task, and null should be returned.
if (MaxThreadsPerTask <= task.getThreadCount()) {
dispatch();
return null;
}
// To link a thread to its task, the method addThread() of class
// IflTaskCB should be used and the thread’s task must be set using
// the method setTask() of IflThreadCB.*/
ThreadCB thread = new ThreadCB();
// null should also be returned if addThread() returns FAILURE. You can
// find out the number of threads a task currently has by calling the
// method getThreadCount() on that task.
if (task.addThread(thread) == FAILURE) {
dispatch();
return null;
}
// Apparently I needed to add this after testing. 2 hours of debugging. Wow
task.addThread(thread);
thread.setTask(task);
// If priority scheduling needs to be implemented, the do create() method must cor-
// rectly assign the thread’s initial priority. The actual value of the priority depends
// on the particular scheduling policy used. OSP 2 provides methods for setting and
// querying the priority of both tasks and threads. The methods are setPriority() and
// getPriority() in classes TaskCB and ThreadCB, respectively.
thread.setPriority(randomGeneratedNumber.nextInt((10 - 1) + 1));
// Finally, the status of the new thread should be set to ThreadReady
// and it should be placed in the ready queue.
thread.setStatus(ThreadReady);
// If priority is above below 10% or equal to move into the low priority thread.
if (task.getPriority() <= 1) ThreadCB.lowPriorityQueue.addElement(thread);
else ThreadCB.highPriorityQueue.addElement(thread);
// If all is well, the thread object created by this method should be returned.
dispatch();
return thread;
}
