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ABADemo.java
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74 lines (65 loc) · 3.12 KB
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package JavaDemo.JUCTest;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicReference;
import java.util.concurrent.atomic.AtomicStampedReference;
/**
* @Author MaoTian
* @Classname ABADemo
* @Description TODO
* @Date 上午11:36 2019/8/11
* @Version 1.0
* @Created by mao<[email protected]>
*/
public class ABADemo {
private static AtomicReference<Integer> atomicReference = new AtomicReference<>(100);
private static AtomicStampedReference<Integer> stampedReference = new AtomicStampedReference<>(100, 1);
public static void main(String[] args) {
System.out.println("===以下是ABA问题的产生===");
new Thread(() -> {
atomicReference.compareAndSet(100, 101);
atomicReference.compareAndSet(101, 100);
}, "t1").start();
new Thread(() -> {
//先暂停1秒 保证完成ABA
try {
TimeUnit.SECONDS.sleep(1);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println(atomicReference.compareAndSet(100, 2019) + "\t" + atomicReference.get());
}, "t2").start();
try {
TimeUnit.SECONDS.sleep(2);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("===以下是ABA问题的解决===");
new Thread(() -> {
int stamp = stampedReference.getStamp();
System.out.println(Thread.currentThread().getName() + "\t 第1次版本号" + stamp + "\t值是" + stampedReference.getReference());
//暂停1秒钟t3线程
try {
TimeUnit.SECONDS.sleep(1);
} catch (InterruptedException e) {
e.printStackTrace();
}
stampedReference.compareAndSet(100, 101, stampedReference.getStamp(), stampedReference.getStamp() + 1);
System.out.println(Thread.currentThread().getName() + "\t 第2次版本号" + stampedReference.getStamp() + "\t值是" + stampedReference.getReference());
stampedReference.compareAndSet(101, 100, stampedReference.getStamp(), stampedReference.getStamp() + 1);
System.out.println(Thread.currentThread().getName() + "\t 第3次版本号" + stampedReference.getStamp() + "\t值是" + stampedReference.getReference());
}, "t3").start();
new Thread(() -> {
int stamp = stampedReference.getStamp();
System.out.println(Thread.currentThread().getName() + "\t 第1次版本号" + stamp + "\t值是" + stampedReference.getReference());
//保证线程3完成1次ABA
try {
TimeUnit.SECONDS.sleep(3);
} catch (InterruptedException e) {
e.printStackTrace();
}
boolean result = stampedReference.compareAndSet(100, 2019, stamp, stamp + 1);
System.out.println(Thread.currentThread().getName() + "\t 修改成功否" + result + "\t最新版本号" + stampedReference.getStamp());
System.out.println("最新的值\t" + stampedReference.getReference());
}, "t4").start();
}
}