CountDownLatch api详解

今天时间学习CountDownLatch api，该类是JUC原子包中的类，通过单元测试代码把所有public api方法跑了一遍，大致了解了底层实现，初学乍练，有很多一知半解的地方，待后续有了深入理解再来补充

 

package test.java.util.concurrent;


import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;

import org.junit.Test;

/**
 * CountDownLatch的测试类
 *
 * @date 2020-07-14 17:31:12
 */
public class CountDownLatchTest {
        class ThreadTest extends Thread{
                private CountDownLatch count;
                ThreadTest(CountDownLatch count){
                        this.count=count;
                }
                @Override
                public void run() {

                        System.out.println(Thread.currentThread().getName()+":"+count.getCount());
                        count.countDown();

                }
        }
        /**
        * 初始化，参数表示线程数量,即AQS中的同步状态
        * @Param
        */
        @Test
        public void testConstruct0()throws Exception{
        CountDownLatch testObj=new CountDownLatch(9);
                ThreadTest test1=new ThreadTest(testObj);
                ThreadTest test2=new ThreadTest(testObj);
                ThreadTest test3=new ThreadTest(testObj);
                ThreadTest test4=new ThreadTest(testObj);
                ThreadTest test5=new ThreadTest(testObj);
                ThreadTest test6=new ThreadTest(testObj);
                ThreadTest test7=new ThreadTest(testObj);
                ThreadTest test8=new ThreadTest(testObj);
                ThreadTest test9=new ThreadTest(testObj);
                test1.start();
                test2.start();
                test3.start();
                test4.start();
                test5.start();
                test6.start();
                test7.start();
                test8.start();
                test9.start();
                testObj.await();
                System.out.println(123);
        }
        /**
         * 一直等待
         * @Param
         */
        @Test
        public void testAwait()throws Exception{
                CountDownLatch testObj=new CountDownLatch(3);
                ThreadTest test1=new ThreadTest(testObj);
                ThreadTest test2=new ThreadTest(testObj);
                ThreadTest test3=new ThreadTest(testObj);
                test1.start();
                test2.start();
                test3.start();
                testObj.await();
                System.out.println(123);
        }
        /**
         * 等待指定时间
         * @Param
         */
        @Test
        public void testAwait1()throws Exception{
                CountDownLatch testObj=new CountDownLatch(3);
                ThreadTest test1=new ThreadTest(testObj);
                ThreadTest test2=new ThreadTest(testObj);
                ThreadTest test3=new ThreadTest(testObj);
                test1.start();
                test2.start();
                test3.start();
                testObj.await(500,TimeUnit.MILLISECONDS);
                System.out.println(123);
        }
        /**
         * 计数器减一操作
         * @Param
         */
        @Test
        public void testCountDown()throws Exception{
                CountDownLatch testObj=new CountDownLatch(3);
                ThreadTest test1=new ThreadTest(testObj);
                ThreadTest test2=new ThreadTest(testObj);
                ThreadTest test3=new ThreadTest(testObj);
                test1.start();
                test2.start();
                test3.start();
                testObj.await(500,TimeUnit.MILLISECONDS);
                System.out.println(123);
        }
        /**
         * 获取当前计数值
         * @Param
         */
        @Test
        public void testGetCount()throws Exception{
                CountDownLatch testObj=new CountDownLatch(3);
                ThreadTest test1=new ThreadTest(testObj);
                ThreadTest test2=new ThreadTest(testObj);
                ThreadTest test3=new ThreadTest(testObj);
                test1.start();
                test2.start();
                test3.start();
                testObj.await(500,TimeUnit.MILLISECONDS);
                System.out.println(123);
        }
        /**
        * toString
        * @Param
        */
        @Test
        public void testToString()throws Exception{
                CountDownLatch testObj=new CountDownLatch(3);
                System.out.println(testObj.toString());
        }


}

 

本文地址：https://blog.csdn.net/u011106263/article/details/107350077