[转载] C#面向对象设计模式纵横谈——16 Interpreter解释器模式

   1:   

   2:  public class MainApp

   3:  {

   4:      static void Main()

   5:      {

   6:          sting roman="五千三百零九万六千四百五十二";    

   7:   

   8:          Context context=new Context(roman);

   9:     

  10:          ArrayList tree=new ArrayList();

  11:          tree.Add(new GeExpresion());

  12:          tree.Add(new ShiExpresion());

  13:          tree.Add(new BaiExpresion());

  14:          tree.Add(new QianExpresion());

  15:          tree.Add(new WanExpresion());

  16:   

  17:          foreach(Expression exp in tree)

  18:          {

  19:             exp.Interpret(context);

  20:          }

  21:   

  22:          Console.WriteLine("{0}={1}",roman,context.Data);

  23:      }

  24:  }

  25:   

  26:  public class Context

  27:  {

  28:      private string statement;

  29:      private int data;

  30:   

  31:      public Context(statement)

  32:      {

  33:          this.statement=statement;

  34:      }

  35:   

  36:      public string Statment

  37:      {

  38:          get{return statement;}

  39:          set{statement=value;}

  40:      }

  41:   

  42:      public string Data

  43:      {

  44:          get{return data;}

  45:          set{data=value;}

  46:      }

  47:  }

  48:   

  49:  public abstract class Expression

  50:  {

  51:      protected Dictionary<string, int> table=new Dictionary<string, int>(9);

  52:      public Expression()

  53:      {

  54:          table.Add("一",1);

  55:          table.Add("二",2);

  56:          table.Add("三",3);

  57:          table.Add("四",4);

  58:          table.Add("五",5);

  59:          table.Add("六",6);

  60:          table.Add("七",7);

  61:          table.Add("八",8);

  62:          table.Add("九",9);

  63:      }

  64:   

  65:      public virtual void Interpret(Context context)

  66:      {

  67:          if(context.Statement.Length==0)

  68:          {

  69:              return;

  70:          }

  71:   

  72:          foreach(string key in table.Keys)

  73:          {

  74:              int value=table[key];

  75:   

  76:              if(context.Statement.EndsWith(key+GetPostfix()))

  77:              {

  78:                  context.Data+=value*this.Multiplier();

  79:                  context.Statement=context.Statement.Substring(0,context.Statement.Length-1);

  80:              }

  81:   

  82:              if(context.Statement.EndsWith("零"))

  83:              {

  84:                  context.Statement=context.Statement.Substring(0,context.Statement.Length-this.Getlength());

  85:              }

  86:          }

  87:      }

  88:   

  89:      public abstract string GetPostfix();

  90:      public abstract int Multiplier();

  91:   

  92:      public virtual int GetLength()

  93:      {

  94:          return this.GetPostfix().Lenght+1;

  95:      }

  96:  }

  97:   

  98:  public class WanExpression:Expression

  99:  {

 100:      public override string GetPostfix()

 101:      {

 102:          return "万";

 103:      }

 104:   

 105:      public override void Interpret(Context context)

 106:      {

 107:          if(context.Statement.Length==0)

 108:          {

 109:              return;

 110:          }

 111:   

 112:          ArrayList tree=new ArrayList();

 113:          tree.Add(new GeExpresion());

 114:          tree.Add(new ShiExpresion());

 115:          tree.Add(new BaiExpresion());

 116:          tree.Add(new QianExpresion());

 117:   

 118:          foreach(string key in table.Keys)

 119:          {

 120:              int temp=context.Data;

 121:              context.Data=0;

 122:   

 123:              context.Statement=context.Statement.Substring(0,context.Statement.Length-1);

 124:              

 125:              foreach(Expression exp in tree)

 126:              {

 127:                  exp.Interpret(context);

 128:              }

 129:   

 130:              context.Data=temp+this.Multiplier()*context.Data;

 131:          }

 132:      }

 133:   

 134:      public overrride Multiplier(){return 1000;}

 135:  }

 136:   

 137:  public class QianExpression:Expression

 138:  {

 139:      public override string GetPostfix()

 140:      {

 141:          return "千";

 142:      }

 143:   

 144:      public overrride int Multiplier(){return 1000;}

 145:  }

 146:   

 147:  public class BaiExpression:Expression

 148:  {

 149:      public override string GetPostfix()

 150:      {

 151:          return "百";

 152:      }

 153:   

 154:      public overrride int Multiplier(){return 100;}

 155:  }

 156:   

 157:  public class ShiExpression:Expression

 158:  {

 159:      public override string GetPostfix()

 160:      {

 161:          return "十";

 162:      }

 163:   

 164:      public overrride int Multiplier(){return 10;}

 165:  }

 166:   

 167:  public class GeExpression:Expression

 168:  {

 169:      public override string GetPostfix()

 170:      {

 171:          return "";

 172:      }

 173:   

 174:      public overrride int Multiplier(){return 1;}

 175:   

 176:      public override int GetLength()

 177:      {

 178:          return 1;

 179:      }

 180:  }