状态者模式

下面是设计的UML类图：

类总括：

 

  1 using System;
  2 using System.Collections.Generic;
  3 using System.Linq;
  4 using System.Text;
  5 using System.Threading.Tasks;
  6 
  7 namespace Club
  8 {
  9     class Program
 10     {
 11         static void Main(string[] args)
 12         {
 13             Account account = new Account("Legend", 270);
 14             Console.WriteLine("Successed!");
 15             Console.WriteLine("Name:{0}", account.Owner);
 16             Console.WriteLine("Initial:{0}", account.Balance);
 17             Console.WriteLine("------------------");
 18 
 19             account.Cost(250);
 20             Console.WriteLine("-----------------------------------------");
 21 
 22             account.Deposit(100);
 23             Console.WriteLine("-------------------");
 24 
 25             account.Deposit(200);
 26             Console.WriteLine("-----------------------------------------");
 27 
 28             account.Cost(300);
 29             Console.WriteLine("--------------------");
 30 
 31             account.Deposit(999);
 32             Console.WriteLine("-----------------------------------------");
 33 
 34             account.Cost(700);
 35             Console.WriteLine("---------------------");
 36 
 37             account.Cost(123);
 38             Console.WriteLine("-----------------------------------------");
 39 
 40             Console.ReadLine();
 41         }
 42     }
 43 }
 44 class Account
 45 {
 46     public ClientState State{get;set;}
 47     public string Owner{get;set;}
 48     public double Balance{get;set;}
 49 
 50     public Account(string owner,double initialAmount)
 51     {
 52         Owner=owner;
 53         Balance=initialAmount;
 54         State=new VistorState(this);
 55     }
 56 
 57     public void SetBalance(double amount)
 58     {
 59         Balance=amount;
 60     }
 61 
 62     public void Deposit(double amount)
 63     {
 64         Console.WriteLine("Now,deposit {0}.", amount);
 65         State.Deposit(amount);
 66         Console.WriteLine("ClientState turn to {0}", State);
 67     }
 68 
 69     public void Cost(double amount)
 70     {
 71         Console.WriteLine("Now,Cost {0}.", amount);
 72         State.Cost(amount);
 73         Console.WriteLine("ClientState turn to {0}", State);
 74     }
 75 }
 76 abstract class ClientState
 77 {
 78     protected Account Account;
 79     public abstract void Deposit(double amount);
 80     public abstract void Cost(double amount);
 81     public abstract void Check();
 82 }
 83 class VistorState : ClientState
 84 {
 85     public VistorState(Account account)
 86     {
 87         Account=account;
 88     }
 89 
 90     public override void Deposit(double amount)
 91     {
 92          Account.Balance+=amount;
 93         Console.WriteLine("Deposit {0} to {1},surplus of account have {2} affter deposit", amount, Account.Owner, Account.Balance);
 94         Check();
 95     }
 96 
 97     public override void Cost(double amount)
 98     {
 99          double newBalance=Account.Balance-amount;
100         Account.Balance-=amount;
101         Console.WriteLine("Cost {0} from {1},surplus of account have {2} affter cost", amount, Account.Owner, Account.Balance);
102         Check();
103     }
104     public override void Check()
105     {
106          if(Account.Balance>100 && Account.Balance<1000)
107         {
108             Account.State=new MemberState(Account);
109         }
110         else if(Account.Balance>=1000)
111         {
112              Account.State=new VIPState(Account);
113         }
114     }
115 }
116 class MemberState : ClientState
117 {
118     public MemberState(Account account)
119     {
120         Account=account;
121     }
122 
123     public override void Deposit(double amount)
124     {
125          Account.Balance+=amount;
126         Console.WriteLine("Deposit {0} to {1},surplus of account have {2} affter deposit", amount, Account.Owner, Account.Balance);
127         Check();
128     }
129 
130     public override void Cost(double amount)
131     {
132          double newBalance=Account.Balance-amount;
133         Account.Balance-=amount;
134         Console.WriteLine("Cost {0} from {1},surplus of account have {2} affter cost", amount, Account.Owner, Account.Balance);
135         Check();
136     }
137     public override void Check()
138     {
139          if(Account.Balance>0 && Account.Balance<=100)
140         {
141             Account.State = new VistorState(Account);
142         }
143         else if(Account.Balance>=1000)
144         {
145              Account.State=new VIPState(Account);
146         }
147     }
148 }
149 class VIPState : ClientState
150 {
151     public VIPState(Account account)
152     {
153         Account=account;
154     }
155 
156     public override void Deposit(double amount)
157     {
158          Account.Balance+=amount;
159         Console.WriteLine("Deposit {0} to {1},surplus of account have {2} affter deposit", amount, Account.Owner, Account.Balance);
160         Check();
161     }
162 
163     public override void Cost(double amount)
164     {
165          double newBalance=Account.Balance-amount;
166         Account.Balance-=amount;
167         Console.WriteLine("Cost {0} from {1},surplus of account have {2} affter cost", amount, Account.Owner, Account.Balance);
168         Check();
169     }
170     public override void Check()
171     {
172          if(Account.Balance>100 && Account.Balance<1000)
173         {
174             Account.State=new MemberState(Account);
175         }
176         else if (Account.Balance > 0 && Account.Balance <=100)
177         {
178             Account.State = new VistorState(Account);
179         }
180     }
181 }

运行结果：

 

优点：

　　1.封装了转换规则；

　　2. 方便增加 新的状态；

　　3. 允许状态转换逻辑与状态对象合成一体；

　　4. 环境对象可共享状态对象。

缺点：

　　1.结构及实现复杂；

　　2.代码更显得累赘；

　　3.不太支持OCP。