自旋锁

自旋锁

spinlock

自定义自旋锁测试实例

package com.sw.lock;

import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicReference;

/**
 * @Author suaxi
 * @Date 2021/2/22 23:21
 * 自定义自旋锁
 */
public class SpinLockTest {

    AtomicReference<Thread> atomicReference = new AtomicReference<>();

    //加锁
    public void myLock() {
        Thread thread = Thread.currentThread();
        System.out.println(Thread.currentThread().getName() + "--->myLock()");

        //自旋锁
        while (!atomicReference.compareAndSet(null, thread)) {

        }
    }

    //解锁
    public void myUnlock() {
        Thread thread = Thread.currentThread();
        System.out.println(Thread.currentThread().getName() + "--->myUnlock()");
        atomicReference.compareAndSet(thread, null);
    }


    //测试
    public static void main(String[] args) throws InterruptedException {
        SpinLockTest lock = new SpinLockTest();

        new Thread(() -> {
            lock.myLock();
            try {
                TimeUnit.SECONDS.sleep(5);
            } catch (InterruptedException e) {
                e.printStackTrace();
            } finally {
                lock.myUnlock();
            }
        }, "A").start();

        TimeUnit.SECONDS.sleep(2);

        new Thread(() -> {
            lock.myLock();
            try {
                TimeUnit.SECONDS.sleep(3);
            } catch (InterruptedException e) {
                e.printStackTrace();
            } finally {
                lock.myUnlock();
            }
        }, "B").start();

        /*
        执行结果为：
        A--->myLock()
        B--->myLock()
        A--->myUnlock()
        B--->myUnlock()
         */
    }
}