package test1;

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



/**
 * 用Lock和Condition，实现主线程执行5次，子线程再执行10次，孙线程执行15次，如此反复5次
 * 
 * 设计思想：
 * 业务类Business中，设计3个方法，每个方法代表主、子、孙
 * 主方法中执行5次
 * 子方法中执行10次
 * 孙方法中执行15次
 * 
 * 用lock锁住各自方法，然后用runFlag来判断是否自己执行，如果不是，则await，如果走完，则把runFlag设为下一个要执行的对象
 * 然后用condition来唤醒下一线程
 *
 */
public class CommunicationTest3 {
  
  
  public static void main(String[] args) {
    
    final Business2 business = new Business2();
    
    new Thread(new Runnable() {
      @Override
      public void run() {
        for (int i = 0; i < 5; i++) {
          business.sub2(i);
        }
      }
    }){}.start();
    
    new Thread(new Runnable() {
      @Override
      public void run() {
        for (int i = 0; i < 5; i++) {
          business.sub3(i);
        }
      }
    }){}.start();
    
    for (int i = 0; i < 5; i++) {
      business.sub(i);
    }
  }
}

class Business2 {
  private int runFlag = 1;
  private Lock lock = new ReentrantLock();
  Condition c1 = lock.newCondition();
  Condition c2 = lock.newCondition();
  Condition c3 = lock.newCondition();
  
  public void sub(int i) {
    lock.lock();
    try {
      if (runFlag != 1) {
        try {
          c1.await(); // 如果不是sub1执行时，让出CPU
        } catch (Exception e) {
          e.printStackTrace();
        }
      }
      for (int j = 0; j < 5; j++) {
        System.out.println("sub1-" + i + "下的" + j + "次");
      }
      runFlag = 2; // 执行完后，让sub执行
      c2.signal();
    } finally {
      lock.unlock();
    }
  }
  
  public void sub2(int i) {
    lock.lock();
    try {
      if (runFlag != 2) {
        try {
          c2.await(); // 如果不是sub2该执行时，让出CPU
        } catch (Exception e) {
          e.printStackTrace();
        }
      }
      for (int j = 0; j < 10; j++) {
        System.out.println("sub2-" + i + "下的" + j + "次");
      }
      runFlag = 3; // 执行完后，让sub执行
      c3.signal();
    } finally {
      lock.unlock();
    }
  }
  
  public void sub3(int i) {
    lock.lock();
    try {
      if (runFlag != 3) {
        try {
          c3.await(); // 如果不是sub3该执行时，让出CPU
        } catch (Exception e) {
          e.printStackTrace();
        }
      }
      for (int j = 0; j < 15; j++) {
        System.out.println("sub3-" + i + "下的" + j + "次");
      }
      runFlag = 1; // 执行完后，让sub1执行
      c1.signal();
    } finally {
      lock.unlock();
    }
  }
}