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

/**
 * Lock下提供了一个condition条件，其中的condition提供了await和signal两个方法，
 * 起作用和Object提供的wait和notify相同，一个lock下可以有多个condition。
 * 
 * @author
 *
 *    例子，使用lock实现互斥，condition实现通信，来做子线程打印10次，主线程打印100次，如此反复
 */
public class ConditionTest {

    public static void main(String[] args) {
        final Business business = new Business();
        new Thread(new Runnable() {
            @Override
            public void run() {
                while (true) {
                    business.sub();
                }
            }
        }).start();

        while (true) {
            business.main();
        }
    }

    // ConditionTest.Business
    static class Business {
        private Lock lock = new ReentrantLock();
        private Condition cond = lock.newCondition();
        private boolean flag = true; // true : main run , false : sub run

        public void main() {
            lock.lock();
            try {
                while (!flag) {
                    try {
                        cond.await();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
                for (int i = 1; i <= 100; i++) {
                    System.out.println("main of loop Number " + i);
                }
                flag = false;
                cond.signal();
            } finally {
                lock.unlock();
            }
        }
        public void sub() {
            lock.lock();
            try {
                while (flag) {
                    try {
                        cond.await();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
                for (int i = 1; i <= 10; i++) {
                    System.out.println("sub of loop Number" + i);
                }
                flag = true;
                cond.signal();
            } finally {
                lock.unlock();
            }
        }
    }
}