CountDownLatch并发编程

1.定义一个子弹池类

package countdownlatch;

public class BulletPool {

//总共的子弹数量
public static Integer maxBullet = 40000;

   // 拿子弹方法，拿了多少子弹就减少多少
   public Integer getBullet(Integer bulnum){
       maxBullet=maxBullet-bulnum;
       return bulnum;
   }
}

2.定义一个弹匣类

package countdownlatch;

public class Magazine {

   //表示一发弹匣能装多少子弹
   public Integer bulnum = 40;

   public void reduceBul(){
       bulnum=bulnum-1;
   }
}

3..业务抽象出来的补充弹药线程

package countdownlatch;

//业务抽象出来的补充弹药线程
public class SupplementBul implements Runnable{

   MachineGun mg ;

   public SupplementBul(MachineGun mg){
       this.mg=mg;
   }

   //补充弹药方法
   public void supplementBul(){

       try {
           MachineGun.latch.await();
       } catch (InterruptedException e) {
           e.printStackTrace();
       }
       synchronized (mg) {
           //开始补充弹药
           for(int i = 0 ; i < mg.mgList.size();i++){
               mg.mgList.get(i).bulnum=40;
           }
           //补充完弹药通知其他线程可以拿枪开始射击了
           System.out.println("弹药补充完毕，开始射击！！！");
           mg.notifyAll();
       }

   }

   @Override
   public void run() {
       supplementBul();
   }
}

4.定义一个枪类。，并开始射击

package countdownlatch;

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

public class MachineGun extends Thread {

   static CountDownLatch latch = new CountDownLatch(5);

   //出门能带多少弹匣
   public ArrayList<Magazine> mgList;

   public MachineGun(ArrayList<Magazine> mgList){
       this.mgList=mgList;
   }


   @Override
   public void run() {
       shot();
   }

   //射击方法
   public void shot(){
       while(true){
           synchronized (this) {
               if(this.mgList.size()>0){
                   //循环遍历弹匣
                   int i = 1;
                   for(Magazine mg : mgList){
                       //开始射击
                       for(int j = 0 ; j < 40;j++){
                           //System.out.println("第"+(i+1)+"个弹匣还剩"+mgList.get(i).bulnum+"个子弹");
                           mg.reduceBul();
                       }

                       //当前弹匣打完就扔掉
                       if(mg.bulnum==0){
                           System.out.println("打完第"+i+"个弹匣");
                       }
                       i++;
                   }
                   // 减少CountDownLatch中的等待数量
                   latch.countDown();
               }else{
                   try {

                       this.wait();
                       System.out.println("子弹打完，准备上膛");
                   } catch (InterruptedException e) {
                       e.printStackTrace();
                   }
               }
           }
       }
   }

   public static void main(String[] args) {
       //创建5个弹匣
       ArrayList<Magazine> mgList = new ArrayList<Magazine>();
       for( int i = 0 ; i < 5 ; i ++){
           Magazine mg = new Magazine();
           mgList.add(mg);
       }

       //加入到随身行李
       MachineGun mg = new MachineGun(mgList);
       //开始执行
       mg.start();

       SupplementBul sb = new SupplementBul(mg);
       sb.run();

   }
}

CountDownLatch并发编程

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