乐在其中设计模式(C#) - 责任链模式(Chain of Responsibility Pattern)

原文:乐在其中设计模式(C#) - 责任链模式(Chain of Responsibility Pattern)

作者：webabcd

介绍

为解除请求的发送者和接收者之间耦合，而使多个对象都有机会处理这个请求。将这些对象连成一条链，并沿着这条链传递该请求，直到有一个对象处理它。

示例

有一个Message实体类，某个类对它的操作有Insert()方法。现在要求根据插入信息的字符长度，让不同的对象去处理，这些对象连成一条链，并沿着这条链传递该请求，直到有一个对象处理它。

乐在其中设计模式(C#) - 责任链模式(Chain of Responsibility Pattern)-LMLPHP

MessageModel

using System;

using System.Collections.Generic;

using System.Text;

namespace Pattern.ChainOfResponsibility

{

/**//// <summary>

/// Message实体类

/// </summary>

public class MessageModel

{

/**//// <summary>

/// 构造函数

/// </summary>

/// <param name="msg">Message内容</param>

/// <param name="pt">Message发布时间</param>

public MessageModel(string msg, DateTime pt)

{

this._message = msg;

this._publishTime = pt;

}

private string _message;

/**//// <summary>

/// Message内容

/// </summary>

public string Message

{

get

{ return _message; }

set

{ _message = value; }

}

private DateTime _publishTime;

/**//// <summary>

/// Message发布时间

/// </summary>

public DateTime PublishTime

{

get

{ return _publishTime; }

set

{ _publishTime = value; }

}

SqlMessage

using System;

using System.Collections.Generic;

using System.Text;

namespace Pattern.ChainOfResponsibility

{

/**//// <summary>

/// Sql方式操作Message

/// </summary>

public class SqlMessage

{

/**//// <summary>

/// 插入Message

/// </summary>

/// <param name="mm">Message实体对象</param>

/// <returns></returns>

public bool Insert(MessageModel mm)

{

// 代码略

return true;

}

AbstractExecutor

using System;

using System.Collections.Generic;

using System.Text;

namespace Pattern.ChainOfResponsibility

{

/**//// <summary>

/// 抽象处理者(Handler)角色

/// </summary>

public abstract class AbstractExecutor

{

/**//// <summary>

/// 抽象处理者(Handler)角色

/// </summary>

protected AbstractExecutor _executor;

/**//// <summary>

/// 设置责任链的上一级对象

/// </summary>

/// <param name="executor"></param>

public void SetSuccessor(AbstractExecutor executor)

{

this._executor = executor;

}

/**//// <summary>

/// 插入Message

/// </summary>

/// <param name="mm">Message实体对象</param>

/// <returns>执行者；内容；时间</returns>

public abstract string Insert(MessageModel mm);

}

Employee

using System;

using System.Collections.Generic;

using System.Text;

namespace Pattern.ChainOfResponsibility

{

/**//// <summary>

/// 具体处理者(ConcreteHandler)角色

/// </summary>

public class Employee : AbstractExecutor

{

/**//// <summary>

/// 插入Message

/// </summary>

/// <param name="mm">Message实体对象</param>

/// <returns>执行者；内容；时间</returns>

public override string Insert(MessageModel mm)

{

string rtn = "";

// 插入的信息字符数小于5

)

{

SqlMessage m = new SqlMessage();

if (m.Insert(mm))

{

rtn = "执行者：雇员" + " 内容：" + mm.Message + " 时间：" + mm.PublishTime.ToString();

}

// 否则让上级去执行

else if (base._executor != null)

{

rtn = _executor.Insert(mm);

}

return rtn;

}

Leader

using System;

using System.Collections.Generic;

using System.Text;

namespace Pattern.ChainOfResponsibility

{

/**//// <summary>

/// 抽象处理者(Handler)角色

/// </summary>

public class Leader : AbstractExecutor

{

/**//// <summary>

/// 插入Message

/// </summary>

/// <param name="mm">Message实体对象</param>

/// <returns>执行者；内容；时间</returns>

public override string Insert(MessageModel mm)

{

string rtn = "";

// 插入的信息字符数小于10

)

{

SqlMessage m = new SqlMessage();

if (m.Insert(mm))

{

rtn = "执行者：主管" + " 内容：" + mm.Message + " 时间：" + mm.PublishTime.ToString();

}

// 否则让上级去执行

else if (base._executor != null)

{

rtn = _executor.Insert(mm);

}

return rtn;

}

Manager

using System;

using System.Collections.Generic;

using System.Text;

namespace Pattern.ChainOfResponsibility

{

/**//// <summary>

/// 抽象处理者(Handler)角色

/// </summary>

public class Manager : AbstractExecutor

{

/**//// <summary>

/// 插入Message

/// </summary>

/// <param name="mm">Message实体对象</param>

/// <returns>执行者；内容；时间</returns>

public override string Insert(MessageModel mm)

{

string rtn = "";

// 插入的信息字符数小于15

)

{

SqlMessage m = new SqlMessage();

if (m.Insert(mm))

{

rtn = "执行者：经理" + " 内容：" + mm.Message + " 时间：" + mm.PublishTime.ToString();

}

else

{

rtn = "你所插入的Message不符合要求";

}

return rtn;

}

client

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.ChainOfResponsibility;

public partial class ChainOfResponsibility : System.Web.UI.Page

{

protected void Page_Load(object sender, EventArgs e)

{

AbstractExecutor employee = new Employee();

AbstractExecutor leader = new Leader();

AbstractExecutor manager = new Manager();

employee.SetSuccessor(leader);

leader.SetSuccessor(manager);

Response.Write(employee.Insert(new MessageModel("abcd", DateTime.Now)));

Response.Write("<br />");

Response.Write(employee.Insert(new MessageModel("abcdefgh", DateTime.Now)));

Response.Write("<br />");

Response.Write(employee.Insert(new MessageModel("abcdefghigkl", DateTime.Now)));

Response.Write("<br />");

Response.Write(employee.Insert(new MessageModel("abcdefghigklmnop", DateTime.Now)));

}

运行结果

执行者：雇员内容：abcd 时间：2007-4-22 20:04:41

执行者：主管内容：abcdefgh 时间：2007-4-22 20:04:41

执行者：经理内容：abcdefghigkl 时间：2007-4-22 20:04:41

你所插入的Message不符合要求

参考

http://www.dofactory.com/Patterns/PatternChain.aspx

OK

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