返回“設計模式(C#)系列文章索引”
介紹
運用共享技術有效地支持大量細粒度的對象。
示例
有一個Message實體類,某些對象對它的操作有Insert()和Get()方法,現在要運用共享技術支持這些對象。
MessageModel
using System;
using System.Collections.Generic;
using System.Text;
namespace Pattern.Flyweight
{
/**//// <summary>
/// Message實體類
/// </summary>
public class MessageModel
{
/**//// <summary>
/// 構造函數
/// </summary>
/// <param name="msg">Message內容</param>
/// <param name="pt">Message發布時間</param>
public MessageModel(string msg, DateTime pt)
{
this._message = msg;
this._publishTime = pt;
}
private string _message;
/**//// <summary>
/// Message內容
/// </summary>
public string Message
{
get { return _message; }
set { _message = value; }
}
private DateTime _publishTime;
/**//// <summary>
/// Message發布時間
/// </summary>
public DateTime PublishTime
{
get { return _publishTime; }
set { _publishTime = value; }
}
}
}
AbstractMessage
using System;
using System.Collections.Generic;
using System.Text;
namespace Pattern.Flyweight
{
/**//// <summary>
/// 操作Message抽象類(Flyweight)
/// </summary>
public abstract class AbstractMessage
{
/**//// <summary>
/// 獲取Message
/// </summary>
/// <returns></returns>
public abstract List<MessageModel> Get();
/**//// <summary>
/// 插入Message
/// </summary>
/// <param name="mm">Message實體對象</param>
/// <returns></returns>
public abstract bool Insert(MessageModel mm);
}
}
SqlMessage
using System;
using System.Collections.Generic;
using System.Text;
namespace Pattern.Flyweight
{
/**//// <summary>
/// Sql方式操作Message(ConcreteFlyweight)
/// </summary>
public class SqlMessage : AbstractMessage
{
/**//// <summary>
/// 獲取Message
/// </summary>
/// <returns></returns>
public override List<MessageModel> Get()
{
List<MessageModel> l = new List<MessageModel>();
l.Add(new MessageModel("SQL方式獲取Message", DateTime.Now));
return l;
}
/**//// <summary>
/// 插入Message
/// </summary>
/// <param name="mm">Message實體對象</param>
/// <returns></returns>
public override bool Insert(MessageModel mm)
{
// 代碼略
return true;
}
}
}
XmlMessage
using System;
using System.Collections.Generic;
using System.Text;
namespace Pattern.Flyweight
{
/**//// <summary>
/// Xml方式操作Message(ConcreteFlyweight)
/// </summary>
public class XmlMessage : AbstractMessage
{
/**//// <summary>
/// 獲取Message
/// </summary>
/// <returns></returns>
public override List<MessageModel> Get()
{
List<MessageModel> l = new List<MessageModel>();
l.Add(new MessageModel("XML方式獲取Message", DateTime.Now));
return l;
}
/**//// <summary>
/// 插入Message
/// </summary>
/// <param name="mm">Message實體對象</param>
/// <returns></returns>
public override bool Insert(MessageModel mm)
{
// 代碼略
return true;
}
}
}
MessageFactory
using System;
using System.Collections.Generic;
using System.Text;
namespace Pattern.Flyweight
{
/**//// <summary>
/// Message工廠(FlyweightFactory)
/// </summary>
public class MessageFactory
{
private Dictionary<string, AbstractMessage> _messageObjects = new Dictionary<string, AbstractMessage>();
/**//// <summary>
/// 獲取Message對象
/// </summary>
/// <param name="key">key</param>
/// <returns></returns>
public AbstractMessage GetMessageObject(string key)
{
AbstractMessage messageObject = null;
if (_messageObjects.ContainsKey(key))
{
messageObject = _messageObjects[key];
}
else
{
switch (key)
{
case "xml": messageObject = new SqlMessage(); break;
case "sql": messageObject = new XmlMessage(); break;
}
_messageObjects.Add(key, messageObject);
}
return messageObject;
}
}
}
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.Flyweight;
public partial class Flyweight : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
string[] ary = new string[] { "xml", "sql" };
MessageFactory messageFactory = new MessageFactory();
foreach (string key in ary)
{
AbstractMessage messageObject = messageFactory.GetMessageObject(key);
Response.Write(messageObject.Insert(new MessageModel("插入", DateTime.Now)));
Response.Write("<br />");
Response.Write(messageObject.Get()[0].Message + " " + messageObject.Get()[0].PublishTime.ToString());
Response.Write("<br />");
}
}
}
運行結果
True
SQL方式獲取Message 2007-5-17 22:20:38
True
XML方式獲取Message 2007-5-17 22:20:38
參考
http://www.dofactory.com/Patterns/PatternFlyweight.aspx
OK