JDK5 交通燈模擬控制系統

本系統由 Lamp.java , LampController.java , Road.java 和MainClass.java組成.
Lamp.java :
package com.isoftstone.interview.traffic;
public enum Lamp {
//前進 左拐 右拐
S2N("N2S","S2W",false), S2W("N2E","E2W",false), S2E(null,null,true),
E2W("W2E","E2S",false), E2S("W2N","S2N",false), E2N(null,null,true),
N2S(null,null,false) , N2E(null,null,false), N2W(null,null,true),
W2E(null,null,false) , W2N(null,null,false), W2S(null,null,true);
String opposite;
String next;
boolean lighted;
//構造函數:初始化當前燈
private Lamp(String opposite,String next,boolean lighted){
this.opposite = opposite;
this.next = next;
this.lighted = lighted;
}
//返回當前燈的狀態
public boolean isLighted(){return lighted;}
public void light(){
this.lighted = true;
if(opposite != null){
Lamp.valueOf(opposite).light();
}
System.out.println(name() "is Green. Soon there will be cars crossed the street at six deractions.");
}
public Lamp blackout(){
//關閉當前燈 : 設為false
this.lighted = false;
Lamp nextLamp = null;
if(opposite != null){Lamp.valueOf(opposite).blackout();}
//檢查下一個燈並啟動它
if(next != null){
nextLamp = Lamp.valueOf(next);
System.out.println(name() " to the " next " 's light is Green.");
nextLamp.light();
}
return nextLamp;
}
}
LampController.java
package com.isoftstone.interview.traffic;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
public class LampController {
private Lamp currentLamp;
public LampController(){
currentLamp = Lamp.S2N;
currentLamp.light();
//啟動一個線程 : 每十秒將當前燈設置為紅
Executors.newScheduledThreadPool(1).scheduleAtFixedRate(
new Runnable() {
public void run() {
currentLamp = currentLamp.blackout();
}
},
10,
10,
TimeUnit.SECONDS
);
}
}
Road.java
package com.isoftstone.interview.traffic;
import java.util.List;
import java.util.ArrayList;
import java.util.Random;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
public class Road {
private String name;
private List<String> vehicles = new ArrayList<String>();
public Road(String name){
this.name = name;
//模擬車輛不斷隨機上路的過程
Executors.newSingleThreadExecutor().execute(new Runnable() {
public void run() {
for(int i = 0 ; i < 1000 ;i ){

try {
Thread.sleep((new Random().nextInt(10) 1) * 1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
vehicles.add(Road.this.name "_" i);
}
}
});
//每隔一秒檢查對應的燈是否為綠,如果是 ,則放行一輛車,具體操作為從vehicles集合中移除第一輛車.
Executors.newScheduledThreadPool(1).scheduleAtFixedRate(
new Runnable() {
public void run() {
if(vehicles.size() > 0){
if(Lamp.valueOf(Road.this.name).isLighted()){
System.out.println(vehicles.remove(0) " is traversing");
}
}
}
},
1,
1,
TimeUnit.SECONDS);
}
}
最后在Main方法中啟動系統:public static void main(String[] args) {
String[] deractions = {"S2N","S2W","E2W","E2S","N2S","N2E","W2E","W2N","S2E","E2N","N2W","W2S"};
//模擬十二條方向的路線
for(int i = 0 ; i < deractions.length; i ){
new Road(deractions[i]);
}
//啟動交通燈控制器
new LampController();
}

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