How to use

tryTerminate

method

in

jsr166y.ForkJoinPool

/**
 * Initiates an orderly shutdown in which previously submitted
 * tasks are executed, but no new tasks will be accepted.
 * Invocation has no additional effect if already shut down.
 * Tasks that are in the process of being submitted concurrently
 * during the course of this method may or may not be rejected.
 *
 * @throws SecurityException if a security manager exists and
 *         the caller is not permitted to modify threads
 *         because it does not hold {@link
 *         java.lang.RuntimePermission}{@code ("modifyThread")}
 */
public void shutdown() {
  checkPermission();
  tryTerminate(false, true);
}

/**
 * Attempts to cancel and/or stop all tasks, and reject all
 * subsequently submitted tasks.  Tasks that are in the process of
 * being submitted or executed concurrently during the course of
 * this method may or may not be rejected. This method cancels
 * both existing and unexecuted tasks, in order to permit
 * termination in the presence of task dependencies. So the method
 * always returns an empty list (unlike the case for some other
 * Executors).
 *
 * @return an empty list
 * @throws SecurityException if a security manager exists and
 *         the caller is not permitted to modify threads
 *         because it does not hold {@link
 *         java.lang.RuntimePermission}{@code ("modifyThread")}
 */
public List<Runnable> shutdownNow() {
  checkPermission();
  tryTerminate(true, true);
  return Collections.emptyList();
}

if (w.eventCount < 0 && !tryTerminate(false, false) &&
  (int)prevCtl != 0 && !hasQueuedSubmissions() && ctl == currentCtl) {
  Thread wt = Thread.currentThread();

                  (c & ~(AC_MASK|TC_MASK)))));
if (!tryTerminate(false, false) && w != null) {

/**
 * Initiates an orderly shutdown in which previously submitted
 * tasks are executed, but no new tasks will be accepted.
 * Invocation has no additional effect if already shut down.
 * Tasks that are in the process of being submitted concurrently
 * during the course of this method may or may not be rejected.
 *
 * @throws SecurityException if a security manager exists and
 *         the caller is not permitted to modify threads
 *         because it does not hold {@link
 *         java.lang.RuntimePermission}{@code ("modifyThread")}
 */
public void shutdown() {
  checkPermission();
  shutdown = true;
  tryTerminate(false);
}

/**
 * Attempts to cancel and/or stop all tasks, and reject all
 * subsequently submitted tasks.  Tasks that are in the process of
 * being submitted or executed concurrently during the course of
 * this method may or may not be rejected. This method cancels
 * both existing and unexecuted tasks, in order to permit
 * termination in the presence of task dependencies. So the method
 * always returns an empty list (unlike the case for some other
 * Executors).
 *
 * @return an empty list
 * @throws SecurityException if a security manager exists and
 *         the caller is not permitted to modify threads
 *         because it does not hold {@link
 *         java.lang.RuntimePermission}{@code ("modifyThread")}
 */
public List<Runnable> shutdownNow() {
  checkPermission();
  shutdown = true;
  tryTerminate(true);
  return Collections.emptyList();
}

if (w.eventCount == v) {
  if (shutdown)
    tryTerminate(false);

/**
 * Tries to create and start a worker; minimally rolls back counts
 * on failure.
 */
private void addWorker() {
  Throwable ex = null;
  ForkJoinWorkerThread t = null;
  try {
    t = factory.newThread(this);
  } catch (Throwable e) {
    ex = e;
  }
  if (t == null) {  // null or exceptional factory return
    long c;       // adjust counts
    do {} while (!UNSAFE.compareAndSwapLong
           (this, ctlOffset, c = ctl,
           (((c - AC_UNIT) & AC_MASK) |
            ((c - TC_UNIT) & TC_MASK) |
            (c & ~(AC_MASK|TC_MASK)))));
    // Propagate exception if originating from an external caller
    if (!tryTerminate(false) && ex != null &&
      !(Thread.currentThread() instanceof ForkJoinWorkerThread))
      UNSAFE.throwException(ex);
  }
  else
    t.start();
}

    sc = 0;
} while (steps != 2 || sc != 0);
if (!tryTerminate(false)) {
  if (ex != null)   // possibly replace if died abnormally
    signalWork();

    return true;                      // update next time
if ((!shutdown || !tryTerminate(false)) &&
  (int)c != 0 && parallelism + (int)(nc >> AC_SHIFT) == 0 &&
  blockedCount == 0 && quiescerCount == 0)