大话设计模式之装饰模式

敲了下代码，不是很理解

using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace ConsoleApplication2{    class Program    {        static void Main(string[] args)        {            ConcreteComponenth c = new ConcreteComponenth();            ConcreteDecoratorA ca = new ConcreteDecoratorA();            ConcreteDecoratorB cb = new ConcreteDecoratorB();            ca.SetComponent(c);            cb.SetComponent(ca);            cb.Operation();            Console.ReadLine();        }    }    public abstract class Componenth{        public abstract void Operation();    }    public class ConcreteComponenth:Componenth{        public override void Operation()        {            Console.WriteLine("Concrete Operatiion");        }    }    public abstract class Decorator:Componenth    {        protected Componenth component;        public void SetComponent(Componenth _com)        {            this.component = _com;        }        public override void Operation()        {            if (component!=null)            {                component.Operation();            }            //throw new NotImplementedException();        }    }    public class ConcreteDecoratorA:Decorator{        private string addedState;        public override void Operation()        {            base.Operation();            addedState = "new state";            Console.WriteLine("具体装饰对象A操作！");        }    }    public class ConcreteDecoratorB:Decorator{        public override void Operation()        {            base.Operation();            AddedBehavior();            Console.WriteLine("B operation");        }        void AddedBehavior()        {        }    }}