24 Design modes: Enjoy meta mode (Flyweight pattern)

Enjoy meta mode (Flyweight pattern)

Introduced
Use shared technology to effectively support a large number of fine-grained objects.

Example
There is a message entity class, and some objects have an insert () and get () method for its operations, and these objects are now supported using shared technology.

　　Messagemodel

Using system;using system.collections.generic;using system.text;namespace pattern.flyweight{//<summary>// Message entity class///</summary> public class Messagemodel {//<summary>///constructor// /</summary>//<param name= "msg" >message content </param>//<param name= "PT" >message when released            Room </param> public Messagemodel (String msg, DateTime pt) {this._message = msg;        This._publishtime = pt;        } private string _message; <summary>//message content///</summary> public string Message {get            {return _message;}        set {_message = value;}        } private DateTime _publishtime;            <summary>//Message release time///</summary> public DateTime Publishtime {            get {return _publishtime;}        set {_publishtime = value;}    }}} 

　　Abstractmessage

Using system;using system.collections.generic;using system.text;namespace pattern.flyweight{//    <summary >    ///Operation Message abstract class (Flyweight)        ///</summary> public abstract class Abstractmessage {/ <summary>///Get Message///</summary>//        <returns></returns>        Public Abstract list<messagemodel> Get ();        <summary>///INSERT message///</summary>//        <param name= "MM" >message entity object </ param>        //<returns></returns> public abstract bool Insert (Messagemodel mm);}    }

　　Sqlmessage

Using system;using system.collections.generic;using system.text;namespace pattern.flyweight{//    <summary >    ///SQL Operation message (concreteflyweight)///    </summary> Public    class Sqlmessage: Abstractmessage {//<summary>///        Get message//</summary>//        <returns> </returns> public        override list<messagemodel> Get ()        {            list<messagemodel> l = new List <MessageModel> ();            L.add (New Messagemodel ("SQL Get Message", DateTime.Now));            return l;        }        <summary>///INSERT message///</summary>//        <param name= "MM" >message entity object </ param>        //<returns></returns> public override bool Insert (Messagemodel mm)        {            // The code is slightly            return true;}}    }

　　Xmlmessage

Using system;using system.collections.generic;using system.text;namespace pattern.flyweight{//    <summary >    ///XML operation message (Concreteflyweight)///    </summary> Public    class Xmlmessage: Abstractmessage {//<summary>///        Get message//</summary>//        <returns> </returns> public        override list<messagemodel> Get ()        {            list<messagemodel> l = new List <MessageModel> ();            L.add (New Messagemodel ("XML Get Message", DateTime.Now));            return l;        }        <summary>///INSERT message///</summary>//        <param name= "MM" >message entity object </ param>        //<returns></returns> public override bool Insert (Messagemodel mm)        {            // The code is slightly            return true;}}    }

　　Messagefactory

Using system;using system.collections.generic;using system.text;namespace pattern.flyweight{//<summary>// Message Factory (Flyweightfactory)///</summary> public class Messagefactory {private Dictionary<stri        Ng, abstractmessage> _messageobjects = new dictionary<string, abstractmessage> (); <summary>///Get Message object///</summary>//<param name= "key" >key</param&gt        ; <returns></returns> Public abstractmessage Getmessageobject (string key) {Abstrac            Tmessage 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 = n        EW string[] {"xml", "SQL"};        Messagefactory messagefactory = new Messagefactory ();            foreach (string key in ary) {abstractmessage messageobject = Messagefactory.getmessageobject (key);            Response.Write (Messageobject.insert (New Messagemodel ("Insert", DateTime.Now));            Response.Write ("<br/>"); Response.Write (Messageobject.get () [0]. Message + "" + messageobject.get () [0].            Publishtime.tostring ());        Response.Write ("<br/>"); }    }}

　　Run results
True
SQL Get message 2007-5-17 22:20:38
True
XML way to get message 2007-5-17 22:20:38

24 Design modes: Enjoy meta mode (Flyweight pattern)