黑马程序员交通灯案例

通过张老师的交通灯的例子我认识到了很多：首先是要结合现实生活，明白交通灯的的逻辑，说实话在没听老师的课之前我真不知道交通灯的具体逻辑，其次认识到了画图的重要性，单靠想，自己想一会就把自己绕进去了，画图无疑是解决问题非常好的方法。再次学到了面向对象的设计技巧。好了，下面来看这道题。

1、对象设计：设计一个Road对象操作

设计一个Road类

思路：1.创建一个单线程，模拟车子出现的过程、

2.检查是否为绿灯。

 1 public class Road {
 2     private List<String> vechicles = new ArrayList<String>();
 3     
 4     private String name =null;
 5     public Road(String name){
 6         this.name = name;
 7         
 8         //模拟车辆不断随机上路的过程        
 9         ExecutorService pool = Executors.newSingleThreadExecutor();
10         pool.execute(new Runnable(){
11             public void run(){
12                 for(int i=1;i<1000;i++){
13                     try {
14                         Thread.sleep((new Random().nextInt(10) + 1) * 1000);
15                     } catch (InterruptedException e) {
16                         e.printStackTrace();
17                     }
18                     vechicles.add(Road.this.name + "_" + i);
19                 }                
20             }
21             
22         });
23         
25         ScheduledExecutorService timer =  Executors.newScheduledThreadPool(1);
26         timer.scheduleAtFixedRate(
27                 new Runnable(){
28                     public void run(){
29                         if(vechicles.size()>0){
30                             boolean lighted = Lamp.valueOf(Road.this.name).isLighted();
31                             if(lighted){
32                                 System.out.println(vechicles.remove(0) + " is traversing !");
33                             }
34                         }
35                         
36                     }
37                 },
38                 1,
39                 1,
40                 TimeUnit.SECONDS);
41         
42     }
43 }

灯一共有十二种情况和路情况一样定义灯的枚举

枚举的value方法。

package traffic;

public enum Lamp {
    S2N("N2S","S2W",false),S2W("N2E","E2N",false),E2W("W2E","E2S",false),E2S("W2N","W2S",false),
    N2S(null,null,false),N2E(null,null,false),W2E(null,null,false),W2N(null,null,false),
    S2E(null,null,false),E2N(null,null,false),N2W(null,null,false),W2S(null,null,false);
    private boolean lighted;
    //对应的灯
    private String opposite;
    //下一个灯
    private String next;
    private Lamp(String opposite,String next,boolean lighted){
        this.opposite =opposite;
        this.next=next;
        this.lighted=lighted;
        
    }
    private Lamp(){}
    public boolean isLighted(){
        return lighted;
    }
    public void light(){
        this.lighted=true;
        if(opposite!=null){
            Lamp.valueOf(opposite).lighted=true;
            System.out.println(name() + " lamp is green，下面总共应该有6个方向能看到汽车穿过！");
        }
        
    }
    public Lamp blackOut(){
        this.lighted =false;
        if(opposite!=null){
            Lamp.valueOf(opposite).lighted=false;
        }
        Lamp nextLight =Lamp.valueOf(next);
        System.out.println("绿灯从" + name() + "-------->切换为" + next);    
        if(next!=null)
            nextLight.lighted=true;
        return nextLight;
    }

}

定义灯的控制类

package traffic;

import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

public class LampController {
    private Lamp currentLamp;
    public LampController(){
        currentLamp =Lamp.S2N;
        currentLamp.light();
        ScheduledExecutorService timer = Executors.newScheduledThreadPool(1);
        timer.scheduleAtFixedRate(
                new Runnable(){
                    public void run(){
                        LampController.this.currentLamp =currentLamp.blackOut();
                    }
                }, 
                10, 
                10, 
                TimeUnit.SECONDS);
    }

}

最后是控制的主类

package traffic;

public class MainClass {
    public static void main(String[] args){
        String[] directions ={"S2N","S2W","E2W","E2S","N2S","N2E","W2E","W2N","S2E","E2N","N2W","W2S"};
        for(String direction:directions){
            new Road(direction);
        }
        new LampController();
    }

}

总结：枚举的知识环节薄弱，有待加强。及时学习新知识。

posted on 2012-06-21 15:41 Lincon Ma 阅读(143) 评论(0) 编辑收藏举报

黑马程序员 交通灯案例

黑马程序员交通灯案例