Prototype Design Pattern

Specify the kind of objects to create using a prototypical instance, and create new objects by copying this prototype. Like other creational patterns (Builder, Abstract Factory, and Factory Method), the Prototype design pattern hides object creation from the client. However, instead of creating a non-initialized object, it returns a new object that is initialized with values it copied from a prototype - or sample - object.

using System;
using System.Runtime.Remoting;

namespace Patterns
{
/// <summary>
/// MainApp startup class for .NET optimized
/// Proxy Design Pattern.
/// </summary>
class MainApp
{

static void Main()
{
// Create math proxy
MathProxy proxy = new MathProxy();

// Do the math
Console.WriteLine("4 + 2 = " + proxy.Add(4, 2));
Console.WriteLine("4 - 2 = " + proxy.Sub(4, 2));
Console.WriteLine("4 * 2 = " + proxy.Mul(4, 2));
Console.WriteLine("4 / 2 = " + proxy.Div(4, 2));

// Wait for user
Console.ReadKey();
}
}

/// <summary>
/// The 'Subject' interface
/// </summary>
public interface IMath
{
double Add(double x, double y);
double Sub(double x, double y);
double Mul(double x, double y);
double Div(double x, double y);
}

/// <summary>
/// The 'RealSubject' class
/// </summary>
class Math : MarshalByRefObject, IMath
{
public double Add(double x, double y) { return x + y; }
public double Sub(double x, double y) { return x - y; }
public double Mul(double x, double y) { return x * y; }
public double Div(double x, double y) { return x / y; }
}

/// <summary>
/// The remote 'Proxy Object' class
/// </summary>
class MathProxy : IMath
{
private Math _math;

// Constructor
public MathProxy()
{
// Create Math instance in a different AppDomain
AppDomain ad =
AppDomain.CreateDomain("MathDomain", null, null);

ObjectHandle o = ad.CreateInstance(
"DoFactory.GangOfFour.Proxy.NETOptimized",
"DoFactory.GangOfFour.Proxy.NETOptimized.Math");
_math = (Math)o.Unwrap();
}

public double Add(double x, double y)
{
return _math.Add(x, y);
}

public double Sub(double x, double y)
{
return _math.Sub(x, y);
}

public double Mul(double x, double y)
{
return _math.Mul(x, y);
}

public double Div(double x, double y)
{
return _math.Div(x, y);
}
}
}