JUC习题

练习JUC的题目
语言：Java
来源：LeetCode
打印奇偶数
使用sem比lock要简单一些

class ZeroEvenOdd {
    private int n;
    Semaphore zero = new Semaphore(1);
    Semaphore even = new Semaphore(0);
    Semaphore odd = new Semaphore(0);
    volatile int flag = 1;
    public ZeroEvenOdd(int n) {
        this.n = n;
    }

    // printNumber.accept(x) outputs "x", where x is an integer.
    public void zero(IntConsumer printNumber) throws InterruptedException {
        for (int i = 0; i < n; i++) {
            zero.acquire();
            printNumber.accept(0);
            if((flag & 1) == 1){
                odd.release();
            }else{
                even.release();
            }
        }
    }

    public void even(IntConsumer printNumber) throws InterruptedException {
        for (int i = 2; i <= n; i+=2) {
            even.acquire();
            printNumber.accept(i);
            flag = 1;
            zero.release();
        }
    }

    public void odd(IntConsumer printNumber) throws InterruptedException {
        for (int i = 1; i <= n; i+=2) {
            odd.acquire();
            printNumber.accept(i);
            flag = 2;
            zero.release();
        }
    }
}