1 package study.designmode.statemode;
  2 
  3 public class CandyMachine {
  4 
  5     final static int SoldOutState = 0; //初始狀態
  6     final static int OnReadyState = 1;  //待機狀態
  7     final static int HasCoin = 2;  //準備狀態
  8     final static int SoldState = 3;  //售出狀態
  9 
 10     private int state = SoldOutState; //
 
變數,用於存放當前的狀態值
 11     private int count = 0; //糖果的數目
 12 
 13     public CandyMachine(int count) {
 14         this.count = count;
 15         if (count > 0) {
 16             state = OnReadyState;
 17         }
 18     }
 19 
 20     //投入硬幣行為的時候，通過判斷當前的狀態來匹配所有的狀態.
 21     public void insertCoin() {
 22
 
         switch (state) {
 23         case SoldOutState:
 24             System.out.println("you can't insert coin,the machine sold out!");
 25             break;
 26         case OnReadyState: //只有在待機狀態的時候,投入硬幣行為正確,並將狀態改變為準備狀態
 27             state = HasCoin;
 28             System.out
 29                     .println("you have inserted a coin,next,please turn crank!");
 
 30             break;
 31         case HasCoin:
 32             System.out.println("you can't insert another coin!");
 33 
 34             break;
 35         case SoldState:
 36             System.out.println("please wait!we are giving you a candy!");
 37 
 38             break;
 39         }
 40 
 41     }
 42 
 43     //回退硬幣
 44     public void returnCoin() {
 45         switch (state) {
 46         case SoldOutState:
 47             System.out
 48                     .println("you can't return,you haven't inserted a coin yet!");
 49             break;
 50         case OnReadyState:
 51             System.out.println("you haven't inserted a coin yet!");
 52             break;
 53         case HasCoin:
 54 
 55             System.out.println("coin return!");
 56             state = OnReadyState;
 57 
 58             break;
 59         case SoldState:
 60             System.out.println("sorry,you already have turned the crank!");
 61 
 62             break;
 63         }
 64 
 65     }
 66 
 67     //轉動曲柄
 68     public void turnCrank() {
 69         switch (state) {
 70         case SoldOutState:
 71             System.out.println("you turned,but there are no candies!");
 72             break;
 73         case OnReadyState:
 74             System.out.println("you turned,but you haven't inserted a coin!");
 75             break;
 76         case HasCoin:
 77             System.out.println("crank turn...!");
 78             state = SoldState;
 79             dispense();
 80             break;
 81         case SoldState:
 82             System.out
 83                     .println("we are giving you a candy,turning another get nothing,!");
 84             break;
 85         }
 86 
 87     }
 88 
 89     //觸發發放糖果行為
 90     private void dispense() {
 91         count = count - 1;
 92         System.out.println("a candy rolling out!");
 93         if (count > 0) {
 94             state = OnReadyState;
 95         } else {
 96             System.out.println("Oo,out of candies");
 97             state = SoldOutState;
 98         }
 99 
100     }
101 
102     public void printstate() {
103 
104         switch (state) {
105         case SoldOutState:
106             System.out.println("***SoldOutState***");
107             break;
108         case OnReadyState:
109             System.out.println("***OnReadyState***");
110             break;
111         case HasCoin:
112 
113             System.out.println("***HasCoin***");
114 
115             break;
116         case SoldState:
117             System.out.println("***SoldState***");
118             break;
119         }
120 
121     }
122 }