设计模式学习之原型模式（Prototype）

作用：创建新对象时不需要重新定义类，直接从原型类里拷贝创建新对象
实现要点：克隆。（c#的克隆分为浅表拷贝和深度拷贝，详情参见msdn）
UML:

代码：（注：这段代码来自TerryLee  ，http://www.cnblogs.com/Terrylee/ ，觉得很好，顺便复习了索引器，就照搬了。）

abstract class ColorPrototype
    {
        public abstract ColorPrototype Clone();
    }
    class Color : ColorPrototype
    {
        private int red, green, blue;
        public Color(int red, int green, int blue)
        {
            this.red = red;
            this.blue = blue;
            this.green = green;
        }
        public override ColorPrototype Clone()
        {
            Console.WriteLine("Cloning color RGB: {0,3},{1,3},{2,3}", red, green, blue);
            return this.MemberwiseClone() as ColorPrototype;
        }
    }
    class ColorManager
    {
        Hashtable colors = new Hashtable();
        //indexer
        public ColorPrototype this[string name]
        {
            get 
            {
                return colors[name] as ColorPrototype;
            }
            set 
            {
                colors.Add(name, value);
            }
        }
    }
//---------------------执行-------------------------
 class Program
    {
        static void Main(string[] args)
        {
            ColorManager colormanager = new ColorManager(); // Initialize with standard colors 
            colormanager["red" ] = new Color(255, 0, 0); 
            colormanager["green"] = new Color( 0, 255, 0); 
            colormanager["blue" ] = new Color( 0, 0, 255); // User adds personalized colors 
            colormanager["angry"] = new Color(255, 54, 0); 
            colormanager["peace"] = new Color(128, 211, 128); 
            colormanager["flame"] = new Color(211, 34, 20); 
            Color color;
            // User uses selected colors 
            string name = "red"; 
            color = colormanager[name].Clone() as Color; 
            name = "peace"; 
            color = colormanager[name].Clone() as Color; 
            name = "flame"; 
            color = colormanager[name].Clone() as Color; 
            // Wait for user 
            Console.Read();
        }
    }