adapterpluggabletheory.cs

  using System;
 
  // Adapter Pattern -  Pluggable                       Judith Bishop Aug 2006
  // Adapter can accept any number of pluggable adaptees and targets
  // and route the requests via a delegate, in some cases using the
    //  anonymous delegate construct
 
  // Existing way requests are implemented
  class Adaptee {
    public double Precise (double a, double b) {
      return a/b;
    }
  }
 
  // New standard for requests
  class Target  {
    public string Estimate (int i) {
      return "Estimate is " + (int) Math.Round(i/3.0);
    }
  }
 
  // Implementing new requests via old
  class Adapter : Adaptee {
    public Func <int,string> Request;
    
    // Different constructors for the   expected targets/adaptees
    public Adapter (Adaptee adaptee) {
      // Set the delegate to the new standard
      Request = delegate(int i) {
        return "Estimate based on precision is " + (int) Math.Round(Precise (i,3));
      };
    }
    
    public Adapter (Target target) {
      // Set the delegate to the existing standard
      Request = target.Estimate;
    }
  }
 
  class Client {
     static void  Main () {
       
       Adapter adapter1 = new Adapter (new Adaptee());
       Console.WriteLine(adapter1.Request(5));
       
       Adapter adapter2 = new Adapter (new Target());
       Console.WriteLine(adapter2.Request(5));
    }
  }
/*Output
Estimate based on precision is 2
Estimate is 2
*/