Java Design Patterns Interpreter Patterns

interface IExpression {
   void interpret(Context ic);
}

class Context {
   public String input;
   public Context(String input) {
      this.input = input;
   }//from  w w  w  .j a v  a 2  s . c  om

   public void getBinaryForm(String input) {
      int i = Integer.parseInt(input);
      String binaryString = Integer.toBinaryString(i);
      System.out.println("Binary equivalent of " + input + " is " + binaryString);
   }

   public void printInWords(String input) {
      this.input = input;
      char c[] = input.toCharArray();
      for (int i = 0; i < c.length; i++) {
         switch (c[i]) {
         case '1':
            System.out.println("One ");
            break;
         case '2':
            System.out.println("Two ");
            break;
         case '3':
            System.out.println("Three ");
            break;
         case '4':
            System.out.println("Four ");
            break;
         case '5':
            System.out.println("Five ");
            break;
         case '6':
            System.out.println("Six ");
            break;
         case '7':
            System.out.println("Seven ");
            break;
         case '8':
            System.out.println("Eight ");
            break;
         case '9':
            System.out.println("Nine ");
            break;
         case '0':
            System.out.println("Zero ");
            break;
         default:
            System.out.println("* ");
            break;
         }
      }
   }
}

class StringToBinaryExp implements IExpression {
   private String str;

   public StringToBinaryExp(String s) {
      str = s;
   }

   @Override
   public void interpret(Context ic) {
      ic.getBinaryForm(str);
   }
}

class IntToWords implements IExpression {
   private String str;

   public IntToWords(String str) {
      this.str = str;
   }

   @Override
   public void interpret(Context ic) {
      ic.printInWords(str);
   }
}
public class Main {
   public static void main(String[] args) {
      Context context = new Context("6");
      IExpression exp = new IntToWords("6");
      exp.interpret(context);
      exp = new StringToBinaryExp("6");
      exp.interpret(context);      
   }
}