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

/**
 * Lock和Condition实现等待通知
 */
public class ExpressCond {
    public final static String CITY = "ShangHai";
    private int km;/*快递运输里程数*/
    private String site;/*快递到达地点*/
    private Lock lock = new ReentrantLock();
    private Condition keCond = lock.newCondition();
    private Condition siteCond = lock.newCondition();
    public ExpressCond() {
    }
    public ExpressCond(int km, String site) {
        this.km = km;
        this.site = site;
    }

    /* 变化公里数，然后通知处于wait状态并需要处理公里数的线程进行业务处理*/
    public void changeKm(){
        lock.lock();
        try {
            this.km = 101;
            keCond.signal();
        }finally {
            lock.unlock();
        }
    }

    /* 变化地点，然后通知处于wait状态并需要处理地点的线程进行业务处理*/
    public  void changeSite(){
        lock.lock();
        try {
            this.site = "BeiJing";
            siteCond.signal();
        }finally {
            lock.unlock();
        }
    }

    /*当快递的里程数大于100时更新数据库*/
    public void waitKm(){
        lock.lock();
        try {
            while(this.km<=100) {
                try {
                    keCond.await();
                    System.out.println("check km thread["+Thread.currentThread().getId()
                            +"] has been notifed.");
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }finally {
            lock.unlock();
        }
        System.out.println( Thread.currentThread().getId()+ "the km is " + this.km + ",I will change db");
    }

    /*当快递到达目的地时通知用户*/
    public void waitSite(){
        lock.lock();
        try {
            while(CITY.equals(this.site)) {
                try {
                    siteCond.await();
                    System.out.println("check site thread["+Thread.currentThread().getId()
                            +"] has been notifed.");
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }finally {
            lock.unlock();
        }
        System.out.println("the site is "+this.site+",I will call user");
    }
}

import com.ExpressCond;

/**
 * 测试Lock和Condition实现等待通知
 */
public class TestCond {
    private static ExpressCond express = new ExpressCond(0,ExpressCond.CITY);

    /*检查里程数变化的线程,不满足条件，线程一直等待*/
    private static class CheckKm extends Thread{
        @Override
        public void run() {
            express.waitKm();
        }
    }

    /*检查地点变化的线程,不满足条件，线程一直等待*/
    private static class CheckSite extends Thread{
        @Override
        public void run() {
            express.waitSite();
        }
    }

    public static void main(String[] args) throws InterruptedException {
        for(int i=0;i<3;i++){
            new CheckSite().start();
        }
        for(int i=0;i<3;i++){
            new CheckKm().start();
        }
        Thread.sleep(1000);
        express.changeKm();//快递里程变化
    }
}