CountDownLatch Race

最新推荐文章于 2025-04-22 00:34:07 发布

转载最新推荐文章于 2025-04-22 00:34:07 发布 · 555 阅读

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本文介绍了一个使用Java实现的虚拟赛马程序，通过模拟多个赛马的跑步过程，展示了如何利用线程、并发和计数器等技术特性来创建一个有趣的赛马竞赛模拟。

import java.util.*;
import java.util.concurrent.*;

class Race
{
    private Random rand = new Random();

    private int distance = rand.nextInt(250);
    private CountDownLatch start;
    private CountDownLatch finish;

    private List<String> horses = new ArrayList<String>();

    public Race(String... names)
    {
        this.horses.addAll(Arrays.asList(names));
    }

    public void run()
        throws InterruptedException
    {
        System.out.println("And the horses are stepping up to the gate...");
        final CountDownLatch start = new CountDownLatch(1);
        final CountDownLatch finish = new CountDownLatch(horses.size());
        final List<String> places =
            Collections.synchronizedList(new ArrayList<String>());

        for (final String h : horses)
        {
            new Thread(new Runnable() {
                public void run() {
                    try
                    {
                        System.out.println(h +
                            " stepping up to the gate...");
                        start.await();

                        int traveled = 0;
                        while (traveled < distance)
                        {
                            // In a 0-2 second period of time....
                            Thread.sleep(rand.nextInt(3) * 1000);

                            // ... a horse travels 0-14 lengths
                            traveled += rand.nextInt(15);
                            System.out.println(h +
                                " advanced to " + traveled + "!");
                        }
                        finish.countDown();
                        System.out.println(h +
                            " crossed the finish!");
                        places.add(h);
                    }
                    catch (InterruptedException intEx)
                    {
                        System.out.println("ABORTING RACE!!!");
                        intEx.printStackTrace();
                    }
                }
            }).start();
        }

System.out.println("And... they're off!");
start.countDown();

        finish.await();
        System.out.println("And we have our winners!");
        System.out.println(places.get(0) + " took the gold...");
        System.out.println(places.get(1) + " got the silver...");
        System.out.println("and " + places.get(2) + " took home the bronze.");


    }

public int getDistance() {
return distance;
}

public void setDistance(int distance) {
this.distance = distance;
}
}

public class CDLApp
{
    public static void main(String[] args)
        throws InterruptedException, java.io.IOException
    {
        System.out.println("Prepping...");

        Race r = new Race(
            "Beverly Takes a Bath",
            "RockerHorse",
            "Phineas",
            "Ferb",
            "Tin Cup",
            "I'm Faster Than a Monkey",
            "Glue Factory Reject"
            );

        System.out.println("It's a race of " + r.getDistance() + " lengths");

        System.out.println("Press Enter to run the race....");
        System.in.read();

        r.run();
    }
}