并发编程——使用AtomicStampedReference解决ABA问题

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import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicStampedReference;

public class ABA {

	private static AtomicInteger atomicInteger = new AtomicInteger(100);
	private static AtomicStampedReference<Integer> atomicStampedReference = new AtomicStampedReference<Integer>(100, 0);
	
	public static void main(String[] args) {
		Thread t1 = new Thread(new Runnable() {
			@Override
			public void run() {
				atomicInteger.compareAndSet(100, 101);
				atomicInteger.compareAndSet(101, 100);
			}
		});
		Thread t2 = new Thread(new Runnable() {
			@Override
			public void run() {
				try {
					TimeUnit.SECONDS.sleep(1);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
				boolean flag = atomicInteger.compareAndSet(100, 102);
				System.out.println(flag);
			}
		});
		t1.start();
		t2.start();
		
		Thread t3 = new Thread(new Runnable() {
			@Override
			public void run() {
				try {
					TimeUnit.SECONDS.sleep(1);
				} catch (InterruptedException e) {
				}
				atomicStampedReference.compareAndSet(100, 101, atomicStampedReference.getStamp(), atomicStampedReference.getStamp() + 1);
				atomicStampedReference.compareAndSet(101, 100, atomicStampedReference.getStamp(), atomicStampedReference.getStamp() + 1);
			}
		});
		
		Thread t4 = new Thread(new Runnable() {
			@Override
			public void run() {
				// 必须先取stamp,如果compareAndSet中第三个参数使用atomicStampedReference.getStamp();那就没有意义了
				int stamp = atomicStampedReference.getStamp();
				try {
					TimeUnit.SECONDS.sleep(2);
				} catch (InterruptedException e) {
				}
				boolean flag = atomicStampedReference.compareAndSet(100, 101, stamp, stamp + 1);
				System.out.print("t3:" + flag);
			}
		});
		
		t3.start();
		t4.start();
		while (Thread.activeCount() > 1); 
	}
}