交通灯管理系统

两个项目的设计按照面向对象的程序设计思想：谁拥有数据，谁就提供操作数据的方法。

经典案例：
1、石头、石刀、木头、椅子
      石刀工厂生产石刀，传入的参数是石头，木材由石刀砍出，传入参数为木头，椅子由椅子工厂加工，传入参数为木材
2、画圆
      圆提供画圆的方法，传入的参数是圆心和半径。
3、线和小球的关系
      小球有滚动的方法，线提供小球滚动的方向、下一点的坐标。
4、刹车
      人给车刹车的信号，车提供刹车的方法。
5、关门
      门提供关门的方法：旋转等。
 
       交通灯管理系统：
 

       联系实际，熟悉交通灯的工作方式，十字路口共十二个方向，可简化为四个方向来设计，分别由东边和南边出发，有由东向西、由东向南、由南向西、由南向北四个左转方向要考虑，由西向东、由西向北、由北向东、由北向南四个左转方向为上边四个方向对应，另外有由东向北、由北向西、由西向南、由南向东四个右转方向各由一个常绿灯来控制不限行。
       主要设计三个类：路、路灯、路灯控制器。
1、  路类，路上有车，路提供操作车的方法，产生路面的车辆，车辆是否过路口由路控制，路不断检查对面红绿灯的状况以决定是否对本路面上的车辆放行；
    

public class Road {

private List<String> vechicles = new ArrayList<String>();

private String name =null;

public Road(String name){

this.name = name;

ExecutorService pool = Executors.newSingleThreadExecutor();

pool.execute(new Runnable(){

public void run(){

for(int i=1;i<1000;i++){

try {

Thread.sleep((new Random().nextInt(10) + 1) * 1000);

} catch (InterruptedException e) {

e.printStackTrace();

}

vechicles.add(Road.this.name + "_" + i);

}

}

});

ScheduledExecutorService timer =  Executors.newScheduledThreadPool(1);

timer.scheduleAtFixedRate(

new Runnable(){

public void run(){

if(vechicles.size()>0){

boolean lighted = Lamp.valueOf(Road.this.name).isLighted();

if(lighted){

System.out.println(vechicles.remove(0) + " is traversing !");

}

}

}

},

1,

1,

TimeUnit.SECONDS);

}

}

  
2、  路灯
public enum Lamp {
       S2N("N2S","S2W",false),S2W("N2E","E2W",false),E2W("W2E","E2S",false),E2S("W2N","S2N",false),
       N2S(null,null,false),N2E(null,null,false),W2E(null,null,false),W2N(null,null,false),
       S2E(null,null,true),E2N(null,null,true),N2W(null,null,true),W2S(null,null,true);
       private Lamp(String opposite,String next,boolean lighted){
              this.opposite = opposite;
              this.next = next;
              this.lighted = lighted;
       }
 
       private boolean lighted;
       private String opposite;
       private String next;
       public boolean isLighted(){
              return lighted;
       }
      
       public void light(){
              this.lighted = true;
              if(opposite != null){
                     Lamp.valueOf(opposite).light();
              }
              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).blackOut();
              }           
             
              Lamp nextLamp= null;
              if(next != null){
                     nextLamp = Lamp.valueOf(next);
                     System.out.println("绿灯从" + name() + "-------->切换为" + next);              
                     nextLamp.light();
              }
              return nextLamp;
       }
}
 
3、  路灯控制器
public class LampController {
       private Lamp currentLamp;
      
       public LampController(){
              //刚开始让由南向北的灯变绿;          
              currentLamp = Lamp.S2N;
              currentLamp.light();
             
              //每隔10秒将当前绿灯变为红灯，并让下一个方向的灯变绿      
              ScheduledExecutorService timer =  Executors.newScheduledThreadPool(1);
              timer.scheduleAtFixedRate(
                            new Runnable(){
                                   public  void run(){
                                          System.out.println("来啊");
                                          currentLamp = currentLamp.blackOut();
                            }
                            },
                            10,
                            10,
                            TimeUnit.SECONDS);
       }
}
 
 
4、产生Main方法
public class MainClass {
 
       /**
        * @param args
        */
       public static void main(String[] args) {
              String [] directions = new String[]{
       "S2N","S2W","E2W","E2S","N2S","N2E","W2E","W2N","S2E","E2N","N2W","W2S"
              };
              for(int i=0;i<directions.length;i++){
                     new Road(directions[i]);
              }
             
              //产生整个交通灯系统 
              new LampController();
       }
 
}