head first 设计模式学习随笔(10)----组合模式

所谓组合模式----允许将对象组合形成树形结构来表现“整体/部分”层次结构。组合能让客户以一致的方式处理个别对象以及对象集合

个人认为Xml数据的格式就很类似于组合模式，而XmlNode类适合于组合模式的描述，以下我将以长江源头描述起，来说明组合模式

 

    /// <summary>
    /// 组合模式 抽象类
    /// </summary>
    public abstract class Component
    {
        public abstract string GetInfo();
        public abstract List<Component> GetChilds();
        public abstract void AddChild(Component com);
        public abstract void RemoveChild(Component com);

        /// <summary>
        /// 打印全部信息
        /// </summary>
        public void PrintAll()
        {
            Print(this,0);
        }

        /// <summary>
        /// 递归方法遍历所有
        /// </summary>
        /// <param name="com"></param>
        /// <param name="i"></param>
        private void Print(Component com,int i) 
        {
            Console.WriteLine(GetTab(i) + com.GetInfo());
            List<Component> childs =com.GetChilds();
            if (childs != null)
            {
                foreach (Component list in childs)
                    Print(list, ++i);
            }
        }

        /// <summary>
        /// 这里是tab 为了使得层次更加清晰
        /// </summary>
        /// <param name="i"></param>
        /// <returns></returns>
        private string GetTab(int i)
        {
            string tab="";
            for (int j = 0; j < i; j++)
                tab += "\t";
            return tab;
        }
    }

    /// <summary>
    /// 河 可以有分支溪流组成
    /// </summary>
    public class River : Component
    {
        List<Component> Rivers;
        string info;

        public River(string info)
        {
            Rivers = new List<Component>();
            this.info = info;
        }

        public override string GetInfo()
        {
            return info;
        }

        public override List<Component> GetChilds()
        {
            return this.Rivers;
        }

        public override void AddChild(Component com)
        {
            Rivers.Add(com);
        }

        public override void RemoveChild(Component com)
        {
            Rivers.Remove(com);
        }
    }

    /// <summary>
    /// 溪流 没有分支啦
    /// </summary>
    public class Rivulet : Component
    {
        string info;

        public Rivulet(string info)
        {
            this.info = info;
        }

        public override string GetInfo()
        {
            return info;
        }

        public override List<Component> GetChilds()
        {
            return null;
        }

        #region 以下2个方法不实现

            public override void AddChild(Component com)
            {
                throw new NotImplementedException();
            }

            public override void RemoveChild(Component com)
            {
                throw new NotImplementedException();
            }

        #endregion

    }


    class Program
    {
        static void Main(string[] args)
        {
            River changjiang = new River("长江");
            River yalongjiang = new River("雅砻江");
            River minjiang = new River("岷江");

            Rivulet tuotuohe = new Rivulet("沱沱河");
            Rivulet tongtianhe = new Rivulet("通天河");
            Rivulet daduhe = new Rivulet("大渡河");
            Rivulet jialingjiang = new Rivulet("嘉陵江");
            Rivulet wujiang = new Rivulet("乌江");
            Rivulet yuanjiang = new Rivulet("沅江");
            Rivulet xiangjiang = new Rivulet("湘江");
            Rivulet hanjiang = new Rivulet("汉江");
            Rivulet ganjiang = new Rivulet("赣江");
            Rivulet huangpujiang = new Rivulet("黄浦江");

            yalongjiang.AddChild(daduhe);
            yalongjiang.AddChild(jialingjiang);
            yalongjiang.AddChild(wujiang);

            minjiang.AddChild(yuanjiang);
            minjiang.AddChild(xiangjiang);
            minjiang.AddChild(hanjiang);
            minjiang.AddChild(ganjiang);

            changjiang.AddChild(tuotuohe);
            changjiang.AddChild(tongtianhe);
            changjiang.AddChild(yalongjiang);
            changjiang.AddChild(minjiang);
            changjiang.AddChild(huangpujiang);

            changjiang.PrintAll();

            Console.Read();
        }
    }