AtomicMarkableReference是什么

使用Boolean作为标记，检查引用变量是否修改过。

实例

@Slf4j(topic = "c.Test38")
public class Test38 {
    public static void main(String[] args) throws InterruptedException {
        GarbageBag bag = new GarbageBag("装满了垃圾");
        // 参数2 mark 可以看作一个标记，表示垃圾袋满了
        AtomicMarkableReference<GarbageBag> ref = new AtomicMarkableReference<>(bag, true);
        log.debug("start...");
        GarbageBag prev = ref.getReference();
        log.debug(prev.toString());
        new Thread(() -> {
            log.debug("start...");
            bag.setDesc("空垃圾袋");
            ref.compareAndSet(bag, bag, true, false);
            log.debug(bag.toString());
        },"保洁阿姨").start();
        sleep(1);
        log.debug("想换一只新垃圾袋？");
        boolean success = ref.compareAndSet(prev, new GarbageBag("空垃圾袋"), true, false);
        log.debug("换了么？" + success);
        log.debug(ref.getReference().toString());
    }
}
class GarbageBag {
    String desc;
    public GarbageBag(String desc) {
        this.desc = desc;
    }
    public void setDesc(String desc) {
        this.desc = desc;
    }
    @Override
    public String toString() {
        return super.toString() + " " + desc;
    }
}

01:20:27.060 c.Test38 [main] - start... 01:20:27.061 c.Test38 [main] - cn.itcast.test.GarbageBag@61baa894 装满了垃圾 01:20:27.090 c.Test38 [保洁阿姨] - start... 01:20:27.090 c.Test38 [保洁阿姨] - cn.itcast.test.GarbageBag@61baa894 空垃圾袋 01:20:28.104 c.Test38 [main] - 想换一只新垃圾袋？ 01:20:28.104 c.Test38 [main] - 换了么？false 01:20:28.104 c.Test38 [main] - cn.itcast.test.GarbageBag@61baa894 空垃圾袋