我想创建一个程序来说明马拉松运动员的检查点。创建 5 名运行者,并花费随机的时间到达第一个检查点。参赛者必须在检查点停下来,直到所有其他参赛者都到达检查点。有 2 个检查站和终点线。
这是一些我认为是实现此目的的最佳方法的基本代码:
public class Main {
public static void main(String[] args) {
int i = 1;
Runner[] runners = new Runner[5];
//Create 5 Runners
for (Runner runner : runners) {
runner = new Runner(i++);
runner.run();
}
//Wait for runners to arrive at 1st checkpoint
for (Runner runner : runners) {
runner.arrivedAt1stCheckpoint();
}
//Wait for runenrs to arrive at 2nd checkpoint
for (Runner runner : runners) {
runner.arrivedAt2ndCheckpoint();
}
//Wait for runners to finish race
for (Runner runner : runners) {
runner.finishedRace();
}
}}
public class Runner implements Runnable {
public final int runnerID;
Random randomGenerator = new Random();
public Runner(int i) {
this.runnerID = i;
}
@Override
public void run() {
System.out.printf("Runner %d exists\n", runnerID);
}
public boolean arrivedAt1stCheckpoint() {
sleepThread();
System.out.printf("Runner %d arrived at 1st checkpoint\n", runnerID);
return true;
}
public boolean arrivedAt2ndCheckpoint() {
System.out.printf("Runner %d arrived at 2nd checkpoint\n", runnerID);
sleepThread();
return true;
}
public boolean finishedRace() {
System.out.printf("Runner %d finished race\n", runnerID);
sleepThread();
return true;
}
private void sleepThread() {
try {
Thread.sleep(randomGenerator.nextInt(1000));
} catch (InterruptedException ex) {
Logger.getLogger(Runner.class.getName()).log(Level.SEVERE, null, ex);
}
}}
显然这只是一个结构,我错过了很多东西,所以我不要求为我编写整个程序。 我这里的主要问题是让 Runner 类的每个实例以某种方式与其他实例进行通信,并使整个程序 hibernate ,直到所有 Runner 到达检查点。 任何“指针”都会有帮助,谢谢!
最佳答案
您可能需要考虑 CyclicBarrier 或 CountDownLatch。这是使用 CyclicBarrier 的快速片段。
将屏障设置为您想要的所需计数,将屏障传递给您想要在屏障上等待的线程,如下所示
int BarrierCount = 4;
CyclicBarrier barrier = new CyclicBarrier(BarrierCount);
for (int i = 0; i <= BarrierCount; i++) {
(new AppThreadsForBarrier(barrier, "name"+i, ...)).start();
}
现在在需要等待屏障的线程中,可以执行以下操作
class AppThreadsForBarrier extends Thread {
// barrier along with other variables you need for your thread
public AppThreadsForBarrier(CyclicBarrier barrier, String name, ....) {
..
public void run() {
try {
Thread.sleep(duration);
System.out.println(Thread.currentThread().getName() + " is calling await()");
barrier.await();
System.out.println(Thread.currentThread().getName() + " has started running again");
..
关于在哪里使用 CyclicBarrier 和 CountdownLatch 存在一些细微差别,但这应该可以让您了解如何开始使用。
关于java - 如何暂停一个 Runnable 直到另一个相同类型的任务完成?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/42382111/