自旋锁

package com.itjava.interview;

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

//自旋锁
public class SpinLockDemo {

    //原子引用线程
    AtomicReference<Thread> atomicReference = new AtomicReference<>();  //初始值为null

    public void myLock() {

        Thread thread = Thread.currentThread();
        System.out.println(Thread.currentThread().getName() + "\t come in");

        //使用自旋  反复的使用！
        while (!atomicReference.compareAndSet(null, thread)) {

        }
    }

    public void myUnLock() {
        Thread thread = Thread.currentThread();
        atomicReference.compareAndSet(thread, null);
        System.out.println(Thread.currentThread().getName() + "\t invoked myUnLock");
    }

    public static void main(String[] args) {

        SpinLockDemo spinLockDemo = new SpinLockDemo();

        new Thread(() -> {
            spinLockDemo.myLock();  //上锁
            //暂停一会线程
            try {TimeUnit.SECONDS.sleep(5);} catch (InterruptedException e) {e.printStackTrace();}
            spinLockDemo.myUnLock();  //解锁
        }, "AA").start();

        try {TimeUnit.SECONDS.sleep(1);} catch (InterruptedException e) {e.printStackTrace();}

        new Thread(() -> {
            spinLockDemo.myLock();  //上锁
            spinLockDemo.myUnLock();  //解锁
        }, "BB").start();
    }
}