Factory Method

 简单写的一个Factory Method, 利用反射简化工厂逻辑,在添加/删除产品后不需要更新工厂.

 

using System;
using System.Collections.Generic;

namespace ConsoleApplication1
{
    
    class Program
    {
        static void Main(string[] args)
        {
            Light l;
            l = LightFactory.Create("Bulb");
            l.TurnOn();
            l.TurnOff();

            l = LightFactory.Create("Tube");
            l.TurnOn();
            l.TurnOff();           
        }

    }


    public interface ILightCreator
    {
        Light Create();
    }

    public abstract class Light
    {
        public abstract string Name { get; }
        public abstract void TurnOn();
        public abstract void TurnOff();
    }

    class BulbLight : Light, ILightCreator
    {
        public override void TurnOn()
        {
            Console.WriteLine("Bulb Light is turned on");
        }

        public override void TurnOff()
        {
            Console.WriteLine("Bulb Light is turned off");
        }

        ILightCreator Members#region ILightCreator Members

        public Light Create()
        {
            return new BulbLight();
        }

        #endregion

        public override string Name
        {
            get { return "Bulb"; }
        }
    }

    class TubeLight : Light, ILightCreator
    {
        public override void TurnOn()
        {
            Console.WriteLine("Tube Light is turned on");
        }

        public override void TurnOff()
        {
            Console.WriteLine("Tube light is turned off");
        }

        ILightCreator Members#region ILightCreator Members

        public Light Create()
        {
            return new TubeLight();
        }

        #endregion

        public override string Name
        {
            get { return "Tube"; }
        }
    }

    public class LightFactory
    {
        public static Light Create(string lightType)
        {
            if (ImplementedLightCreator.ContainsKey(lightType))
            {
                ILightCreator creator = ImplementedLightCreator[lightType];
                return creator.Create();
            }
            else
                return new BulbLight();
        }

        static Dictionary<string, ILightCreator> implementedLightCreator;
        public static Dictionary<string, ILightCreator> ImplementedLightCreator
        {
            get
            {
                if (implementedLightCreator == null)
                {                  
                    implementedLightCreator = InitilizeCreator();                   
                }
                return implementedLightCreator;
            }
        }

        private static Dictionary<string, ILightCreator> InitilizeCreator()
        {
            Dictionary<string, ILightCreator> creators = new Dictionary<string, ILightCreator>();

            Type basic = typeof(ILightCreator);
            foreach (Type t in basic.Assembly.GetTypes())
            {
                if (basic.IsAssignableFrom(t) && !t.IsAbstract)
                {
                    ILightCreator instance = (ILightCreator)(Activator.CreateInstance(t));
                    creators[(string)(t.GetProperty("Name").GetValue(instance, null))] = instance;
                }
            }
            return creators;
        }
    }
}