Lock、Condition实现精准唤醒，交替打印ABC

import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

public class book {
    public static void main(String[] args) throws InterruptedException {
        accurateSignal da = new accurateSignal();
        new Thread(()->{
            for(int i = 0; i < 10; i++){
                try {
                    da.printA();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
}).start();
        new Thread(()->{
            for(int i = 0; i < 10; i++){
                try {
                    da.printB();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }).start();
        new Thread(()->{
            for(int i = 0; i < 10; i++){
                try {
                    da.printC();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }).start();
    }
}
class accurateSignal{

     Lock lock = new ReentrantLock();
     Condition a1 = lock.newCondition();
     Condition b1 = lock.newCondition();
     Condition c1 = lock.newCondition();
     int num = 1;
     public void printA() throws InterruptedException {
         lock.lock();
         while(num!=1){
             a1.await();
         }
         System.out.println("A");
         num = 2;
         b1.signal();
         lock.unlock();
     }
    public void printB() throws InterruptedException {
        lock.lock();
        while(num!=2){
            b1.await();
        }
        System.out.println("B");
        num = 3;
        c1.signal();
        lock.unlock();
    }
    public void printC() throws InterruptedException {
        lock.lock();
        while(num!=3){
            c1.await();
        }
        System.out.println("C");
        num = 1;
        a1.signal();
        lock.unlock();
    }
}