Builder

// Builder pattern -- Real World example

using System;
using System.Collections;

namespace DoFactory.GangOfFour.Builder.RealWorld
{
  // MainApp test application

  public class MainApp
  {
    public static void Main()
    {
      // Create shop with vehicle builders
      Shop shop = new Shop();
      VehicleBuilder b1 = new ScooterBuilder();
      VehicleBuilder b2 = new CarBuilder();
      VehicleBuilder b3 = new MotorCycleBuilder();

      // Construct and display vehicles
      shop.Construct(b1);
      b1.Vehicle.Show();

      shop.Construct(b2);
      b2.Vehicle.Show();

      shop.Construct(b3);
      b3.Vehicle.Show();

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

  // "Director"

  class Shop
  {
    // Builder uses a complex series of steps
    public void Construct(VehicleBuilder vehicleBuilder)
    {
      vehicleBuilder.BuildFrame();
      vehicleBuilder.BuildEngine();
      vehicleBuilder.BuildWheels();
      vehicleBuilder.BuildDoors();
    }
  }

  // "Builder"

  abstract class VehicleBuilder
  {
    protected Vehicle vehicle;

    // Property
    public Vehicle Vehicle
    {
      get{ return vehicle; }
    }

    public abstract void BuildFrame();
    public abstract void BuildEngine();
    public abstract void BuildWheels();
    public abstract void BuildDoors();
  }

  // "ConcreteBuilder1"

  class MotorCycleBuilder : VehicleBuilder
  {
    public override void BuildFrame()
    {
      vehicle = new Vehicle("MotorCycle");
      vehicle["frame"] = "MotorCycle Frame";
    }

    public override void BuildEngine()
    {
      vehicle["engine"] = "500 cc";
    }

    public override void BuildWheels()
    {
      vehicle["wheels"] = "2";
    }

    public override void BuildDoors()
    {
      vehicle["doors"] = "0";
    }
  }

  // "ConcreteBuilder2"

  class CarBuilder : VehicleBuilder
  {
    public override void BuildFrame()
    {
      vehicle = new Vehicle("Car");
      vehicle["frame"] = "Car Frame";
    }

    public override void BuildEngine()
    {
      vehicle["engine"] = "2500 cc";
    }

    public override void BuildWheels()
    {
      vehicle["wheels"] = "4";
    }

    public override void BuildDoors()
    {
      vehicle["doors"] = "4";
    }
  }

  // "ConcreteBuilder3"

  class ScooterBuilder : VehicleBuilder
  {
    public override void BuildFrame()
    {
      vehicle = new Vehicle("Scooter");
      vehicle["frame"] = "Scooter Frame";
    }

    public override void BuildEngine()
    {
      vehicle["engine"] = "50 cc";
    }

    public override void BuildWheels()
    {
      vehicle["wheels"] = "2";
    }

    public override void BuildDoors()
    {
      vehicle["doors"] = "0";
    }
  }

  // "Product"

  class Vehicle
  {
    private string type;
    private Hashtable parts = new Hashtable();

    // Constructor
    public Vehicle(string type)
    {
      this.type = type;
    }

    // Indexer (i.e. smart array)
    public object this[string key]
    {
      get{ return parts[key]; }
      set{ parts[key] = value; }
    }

    public void Show()
    {
      Console.WriteLine("\n---------------------------");
      Console.WriteLine("Vehicle Type: {0}", type);
      Console.WriteLine(" Frame : {0}", parts["frame"]);
      Console.WriteLine(" Engine : {0}", parts["engine"]);
      Console.WriteLine(" #Wheels: {0}", parts["wheels"]);
      Console.WriteLine(" #Doors : {0}", parts["doors"]);
    }
  }
}