design pattern

pattern.cs

// ----------- adapter pattern -------------------
public class TargetA
{
    public void Start() { ... }
    public void End() { ... }
}

public class TargetB
{
    public void Begin() { ... }
    public void Terminate() { ... }
}

public interface ITargetAdapter
{
    void Open();
    void Close();
}

public class AdapterA : ITargetAdapter
{
     private TargetA A { get; set; }

     public AdapterA( TargetA a )
     {
           this.A = a;
     }

     public void Open() { this.A.Start(); }
     public void Close() { this.A.End(); }
}

public class AdapterB : ITargetAdapter
{
     private TargetB B { get; set; }

     public AdapterB( TargetB a )
     {
           this.B = a;
     }

     public void Open() { this.B.Begin(); }
     public void Close() { this.B.Terminate(); }
}

ITargetAdapter adapter = new AdapterA( new TargetA() );
adapter.Open();
adapter.Close(); 

// ------------- Singleton -------------------
class Singleton
{
    private static Singleton _instance;
    private static object _lock = new object();

    private Singleton()
    {
    }

    public static Singleton Instance()
    {
        lock(_lock) {
            if (_instance == null)
            {
                _instance = new Singleton();
            }
        }
        return _instance;
    }
}
// ------------ Proxy ---------------------
public class Ops
{
    public virtual Result Transaction()
    {
        Console.WriteLine("Transaction done.");
        return result;
    }
}

public class RpcOps : Ops
{
    public override void Transaction()
    {
        using (TcpClient client = new TcpClient())
        {
            // perform remote procedure call
        }
        return result;
    }
}
// -------------- Decorator -------------------
public abstract class BasePizza
{
    protected double myPrice;

    public virtual double GetPrice()
    {
        return this.myPrice;
    }
}

public abstract class ToppingsDecorator : BasePizza
{
    protected BasePizza pizza;
    public ToppingsDecorator(BasePizza pizzaToDecorate)
    {
        this.pizza = pizzaToDecorate;
    }

    public override double GetPrice()
    {
        return (this.pizza.GetPrice() + this.myPrice);
    }
}

class Program
{
    static void Main()
    {
        Margherita pizza = new Margherita();
        Console.WriteLine("Plain Margherita: " + pizza.GetPrice().ToString());

        ExtraCheeseTopping moreCheese = new ExtraCheeseTopping(pizza);
        ExtraCheeseTopping someMoreCheese = new ExtraCheeseTopping(moreCheese);
        Console.WriteLine("Plain Margherita with double extra cheese: " + someMoreCheese.GetPrice().ToString());

        MushroomTopping moreMushroom = new MushroomTopping(someMoreCheese);
        Console.WriteLine("Plain Margherita with double extra cheese with mushroom: " + moreMushroom.GetPrice().ToString());

        JalapenoTopping moreJalapeno = new JalapenoTopping(moreMushroom);
        Console.WriteLine("Plain Margherita with double extra cheese with mushroom with Jalapeno: " + moreJalapeno.GetPrice().ToString());

        Console.ReadLine();
    }
}

public class Margherita : BasePizza
{
    public Margherita()
    {
        this.myPrice = 6.99;
    }
}

public class Gourmet : BasePizza
{
    public Gourmet()
    {
        this.myPrice = 7.49;
    }
}

public class ExtraCheeseTopping : ToppingsDecorator
{
    public ExtraCheeseTopping(BasePizza pizzaToDecorate)
        : base(pizzaToDecorate)
    {
        this.myPrice = 0.99;
    }
}

public class MushroomTopping : ToppingsDecorator
{
    public MushroomTopping(BasePizza pizzaToDecorate)
        : base(pizzaToDecorate)
    {
        this.myPrice = 1.49;
    }
}

public class JalapenoTopping : ToppingsDecorator
{
    public JalapenoTopping(BasePizza pizzaToDecorate)
        : base(pizzaToDecorate)
    {
        this.myPrice = 1.49;
    }
}

// -------------- Observable -------------------
// -------------- Factory ----------------------