Question

假设我有3个执行线程，下面描述每个线程将执行的操作。

线程1 - 主线程线程2 - 探测器线程线程3 - 动作线程

当线程1启动时，它会生成线程2.线程2将与线程1一起运行并搜索事件。当事件发生时，我希望线程2生成一个新线程，线程3.我希望线程3与线程1连接。这可能吗？

示例代码：

 public class ThreadA {

// variable to flag if ThreadB should still loop
private static boolean runThreadB = true;

public void mainMethod() {

    new ThreadB().start();

    // do some stuff

    // make sure thread B can end
    runThreadB = false;

}

// inner class / Thread B
class ThreadB extends Thread {

    @Override
    public void run() {

        // loop until Thread A is done
        while (runThreadB) {

            // wait for event, if event is found, spawn thread C
            ThreadC threadC = new ThreadC();
            threadC.start();

            /**
             * Need thread C to somehow join ThreadA
             */
            try {
                threadC.join();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }

        }

    }

}

}

 public class ThreadC extends Thread {

@Override
public void run() {

    // perform some tasks

}

}

Answer 1

您必须同步线程。您可以使用ReentrantLock执行此操作。

以下是您的问题的简单示例（事件生产者 - 消费者）：

public class Foo{
    //...

    public void consumeEvent() throws InterruptedException{
        aLock.lock();
        try {
            while(noEvent){
                eventAvailable.await();
            }
            // use the event
        } finally {
            sLock.unlock();
        }
    }

    public void createEvent() throws InterruptedException{
        aLock.lock();
        try {
            // add an event
            eventAvailable.signalAll();
        } finally {
            sLock.unlock();
        }
    }

    private Lock aLock = new ReentrantLock();
    private Condition eventAvailable = aLock.newCondition();
}

您的主题将使用此类中的对象。

Thread eventProducer = ...
Thread eventConsumer = ...
eventProducer.start();
eventConsumer.start();

您的线程现在已同步。

复杂的线程控制

1 个答案: