【Java/CountDownLatch】使用CountDownLatch实现睡眠排序

刚才在 https://news.cnblogs.com/n/703437/ 上看到有人提到有趣的“睡眠排序”，忽然想到CountDownLatch正好可以用于实现一个。代码如下：

package ufo.sleepsort;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.CountDownLatch;

class SleepThread extends Thread{
    private int seconds;
    private List<Integer> ls;
    private CountDownLatch latch;
    
    public SleepThread(int seconds,List<Integer> ls,CountDownLatch latch) {
        this.seconds=seconds;
        this.ls=ls;
        this.latch=latch;
    }
    
    public void run() {
        try {
            Thread.sleep(seconds*1000);
            ls.add(seconds);
            latch.countDown();
        }catch(Exception ex) {
            ex.printStackTrace();
        }
    }
}
public class SleepSortor {
    public static void main(String[] args) throws Exception{
        int[] arr= {2,4,6,13,1,5,7};
        final CountDownLatch latch=new CountDownLatch(arr.length);
        
        List<Integer> ls=new ArrayList<>();
        
        for(int it:arr) {
            SleepThread st=new SleepThread(it,ls,latch);
            st.start();
        }
        
        latch.await();
        
        //排序结束
        for(int i:ls) {
            System.out.println(i);
        }
    }
}

输出：

1
2
4
5
6
7
13

正如预期。

有兴趣的朋友可以参照着试一试。

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