/*

 * 模拟 CAS 算法

 */

public class TestCompareAndSwap {

    public static void main(String[] args) {

        final CompareAndSwap cas = new CompareAndSwap();

        for (int i = 0; i < 10; i++) {

            new Thread(new Runnable() {

                @Override

                public void run() {

                    int expectedValue = cas.get();

                    boolean b = cas.compareAndSet(expectedValue, (int)(Math.random() * 101));

                    System.out.println(b);

                }

            }).start();

        }

    }

}

class CompareAndSwap{

    private int value;

    //获取内存值

    public synchronized int get(){

        return value;

    }

    //比较

    public synchronized int compareAndSwap(int expectedValue, int newValue){

        int oldValue = value;

        if(oldValue == expectedValue){

            this.value = newValue;

        }

        return oldValue;

    }

    //设置

    public synchronized boolean compareAndSet(int expectedValue, int newValue){

        return expectedValue == compareAndSwap(expectedValue, newValue);

    }

}