java - 确保Java线程确实被挂起

Question

我有以下类(class):

public class PawnThread implements Runnable {

    public void start() {
        thread.start();
    }

    @Override
    public void run() {
        try {
            while (... some finish condition ...) {
                move();
                synchronized (this) {
                    while (suspendFlag) {
                        wait();
                    }
                }
            }
        } catch (InterruptedException e) {
            System.err.println(pawn.toString() + ": thread interrupted :(");
        }
    }

    void move() {
        ... some blocking actions
    }

    synchronized void suspend() {
        suspendFlag = true;
    }

    synchronized void resume() {
        suspendFlag = false;
        notify();
    }
}

现在，我有了它的对象的列表:private final List<PawnThread> pawnThreadList;我定义了一些辅助方法来暂停所有这些方法:

public void suspendAll() {
   pawnThreadList.forEach(PawnThread::suspend);
}

现在，suspend()方法仅与更改标志有关。要求是，当我离开suspendAll()方法时，实际上应该暂停所有线程(它们不能处于RUNNABLE状态)-现在不是这种情况了，因为其中某些线程可能需要一些时间才能真正完成其工作。停顿之前。
我将不胜感激，为该解决方案提供正确的设计建议。
问候

Answer 1

使PawnThread#suspend()等待完成挂起:

public class PawnThread implements Runnable {
    private final Waiter suspender = new Waiter();
    private final Waiter suspending = new Waiter();

    @Override
    public void run() {
        try {
            while (...) {
                suspending.suspend();
                move();
                suspending.resume();
                suspender.await();
            }
        } catch (InterruptedException e) {
            ...
        }
    }

    void suspend() throws InterruptedException {
        suspender.suspend();
        suspending.await();
    }

    void resume() {
        suspender.resume();
    }
}

public class Waiter {
    private boolean waiting;

    public synchronized void await() throws InterruptedException {
        while (waiting) {
            wait();
        }
    }

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

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