组合模式(Composite Pattern)

介绍

将对象组合成树形结构以表示“部分-整体”的层次结构。它使得客户对单个对象和复合对象的使用具有一致性。

示例

有一个Message实体类，使其单个对象和复合对象具有一致性。

　　MessageModel

using System;using System.Collections.Generic;using System.Text;namespace Pattern.Composite{    /// 
    /// Message实体类    /// 
    public class MessageModel    {        /// 
        /// 构造函数        /// 
        /// Message内容        /// Message发布时间        public MessageModel(string msg, DateTime pt)        {            this._message = msg;            this._publishTime = pt;        }        private string _message;        /// 
        /// Message内容        /// 
        public string Message        {            get { return _message; }            set { _message = value; }        }        private DateTime _publishTime;        /// 
        /// Message发布时间        /// 
        public DateTime PublishTime        {            get { return _publishTime; }            set { _publishTime = value; }        }    }}

　　MessageModelComponent

using System;using System.Collections.Generic;using System.Text;namespace Pattern.Composite{    /// 
    /// 抽象Message实体构件（Component）    /// 
    public abstract class MessageModelComponent    {        /// 
        /// Message实体对象        /// 
        protected MessageModel _messageModel;        /// 
        /// 名称        /// 
        protected string _name;        /// 
        /// 构造函数        /// 
        /// 名称        /// Message实体对象        public MessageModelComponent(string name, MessageModel mm)        {            this._name = name;            this._messageModel = mm;        }        /// 
        /// 构造函数        /// 
        /// 名称        public MessageModelComponent(string name)        {            this._name = name;        }        /// 
        /// 添加        /// 
        /// MessageModelComponent        public abstract void Add(MessageModelComponent mmc);        /// 
        /// 删除        /// 
        /// MessageModelComponent        public abstract void Remove(MessageModelComponent mmc);        /// 
        /// 获取        /// 
        /// 缩进数        /// 
             public abstract string GetData(int indent);    }}

　　MessageModelLeaf

using System;using System.Collections.Generic;using System.Text;namespace Pattern.Composite{    /// 
    /// Message实体树叶（Leaf）    /// 
    public class MessageModelLeaf : MessageModelComponent    {        /// 
        /// 构造函数        /// 
        /// 名称        /// Message实体对象        public MessageModelLeaf(string name, MessageModel mm)            : base(name, mm)        {                    }        /// 
        /// 添加        /// 
        /// MessageModelComponent        public override void Add(MessageModelComponent mmc)        {            throw new Exception("不能添加");        }        /// 
        /// 删除        /// 
        /// MessageModelComponent        public override void Remove(MessageModelComponent mmc)        {            throw new Exception("不能删除");        }        /// 
        /// 获取        /// 
        /// 缩进数        /// 
             public override string GetData(int indent)        {            return new String('—', indent) +                 "树叶名称：" + _name +                 "；信息内容：" + _messageModel.Message +                 "
";        }    }}

　　MessageModelComposite

using System;using System.Collections.Generic;using System.Text;namespace Pattern.Composite{    /// 
    /// Message实体树枝（Composite）    /// 
    public class MessageModelComposite : MessageModelComponent    {        private List
     
       _list;        /// 
      
        /// 构造函数        /// 
        /// 
      名称        public MessageModelComposite(string name)            : base(name)        {            _list = new List
      
       ();        }        /// 
       
        /// 添加        /// 
        /// 
       MessageModelComponent        public override void Add(MessageModelComponent mmc)        {            _list.Add(mmc);        }        /// 
       
        /// 删除        /// 
        /// 
       MessageModelComponent        public override void Remove(MessageModelComponent mmc)        {            _list.Remove(mmc);        }        /// 
       
        /// 获取        /// 
        /// 
       缩进数        /// 
               public override string GetData(int indent)        {            string s = new String('—', indent) +                 "树枝名称：" + _name +                 "
       
";            foreach (MessageModelComponent mmc in _list)            {                s += mmc.GetData(indent + 2);            }            return s;        }    }}
      
     

　　Test

using System;using System.Data;using System.Configuration;using System.Collections;using System.Web;using System.Web.Security;using System.Web.UI;using System.Web.UI.WebControls;using System.Web.UI.WebControls.WebParts;using System.Web.UI.HtmlControls;using Pattern.Composite;public partial class Composite : System.Web.UI.Page{    protected void Page_Load(object sender, EventArgs e)    {        MessageModelComposite root = new MessageModelComposite("树枝A");        root.Add(new MessageModelLeaf("树叶A", new MessageModel("Message内容A", DateTime.Now)));        root.Add(new MessageModelLeaf("树叶B", new MessageModel("Message内容B", DateTime.Now)));        MessageModelComposite comp = new MessageModelComposite("树枝B");        comp.Add(new MessageModelLeaf("树叶C", new MessageModel("Message内容C", DateTime.Now)));        comp.Add(new MessageModelLeaf("树叶D", new MessageModel("Message内容D", DateTime.Now)));        root.Add(comp);        root.Add(new MessageModelLeaf("树叶E", new MessageModel("Message内容E", DateTime.Now)));        MessageModelLeaf l = new MessageModelLeaf("树叶F", new MessageModel("Message内容F", DateTime.Now));                root.Add(l);        root.Remove(l);        Response.Write(root.GetData(1));    }}

　　运行结果

　　—树枝名称：树枝A

　　———树叶名称：树叶A；信息内容：Message内容A

　　———树叶名称：树叶B；信息内容：Message内容B

　　———树枝名称：树枝B

　　—————树叶名称：树叶C；信息内容：Message内容C

　　—————树叶名称：树叶D；信息内容：Message内容D

　　———树叶名称：树叶E；信息内容：Message内容E