Refactoring to Command

最新推荐文章于 2019-08-19 23:53:23 发布

转载最新推荐文章于 2019-08-19 23:53:23 发布 · 45 阅读

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CC 4.0 BY-SA版权

原文链接：http://www.cnblogs.com/flyingchen/archive/2007/02/05/641290.html

本文通过逐步重构的方式展示了如何改进一个简单的邮件系统。从初始版本到最终版本，通过将具体操作提炼为独立的命令对象，实现了更好的模块化和扩展性。

using System;
using System.Collections.Generic;
using System.Text;

namespace Refactor2Command
{
public class Mail
{
private string sender;

public string Sender
{
get { return sender; }
set { sender = value; }
}
private string receiver;

public string Receiver
{
get { return receiver; }
set { receiver = value; }
}
private DateTime date;

public DateTime Date
{
get { return date; }
set { date = value; }
}
private string body;

public string Body
{
get { return body; }
set { body = value; }
}

public Mail(string _sender, string _receiver, DateTime _date, string _body)
{
sender = _sender;
receiver = _receiver;
date = _date;
body = _body;
}
}

public enum Request
{
SendMail,
ReplyMail,
ReceiveMail,
ForwardMail
}

public class MailSystem
{
private Mail mail;

public Mail Mail
{
get { return mail; }
set { mail = value; }
}

public void Handle(Request request)
{

LogDown();

if (request == Request.SendMail)
{

Console.WriteLine(string.Format("Send Mail To : {0}",mail.Receiver));
}
else if(request == Request.ReceiveMail)
{

Console.WriteLine(string.Format("Receive Mail From:{0}",mail.Sender));
}
else if (request == Request.ForwardMail)
{

Console.WriteLine(string.Format("Forward {0}'s mail to {1} ",mail.Sender,mail.Receiver));
}
else if (request == Request.ReplyMail)
{

Console.WriteLine(string.Format("Reply {0}'s mail on Date:{1}",mail.Sender,mail.Date));
}
}

private void LogDown()
{
Console.WriteLine(string.Format("Mail Sender:{0}", mail.Sender));
Console.WriteLine(string.Format("Mail Receiver:{0}", mail.Receiver));
Console.WriteLine(string.Format("Mail Date:{0}", mail.Date));
Console.WriteLine(string.Format("Mail Body:{0}", mail.Body));
}
}
}

2.简单重构后:

public class MailSystem
{
private Mail mail;

public Mail Mail
{
get { return mail; }
set { mail = value; }
}

public void Handle(Request request)
{
LogDown();

if (request == Request.SendMail)
{
SendMail();
}
else if(request == Request.ReceiveMail)
{
ReceiveMail();
}
else if (request == Request.ForwardMail)
{
ForwardMail();
}
else if (request == Request.ReplyMail)
{
ReplyMail();
}
}

private void ReplyMail()
{
Console.WriteLine(string.Format("Reply {0}'s mail on Date:{1}", mail.Sender, mail.Date));
}

private void ForwardMail()
{
Console.WriteLine(string.Format("Forward {0}'s mail to {1} ", mail.Sender, mail.Receiver));
}

private void ReceiveMail()
{
Console.WriteLine(string.Format("Receive Mail From:{0}", mail.Sender));
}

private void SendMail()
{
Console.WriteLine(string.Format("Send Mail To : {0}", mail.Receiver));
}

3.封装了命令

public class MailSystem
{
private Mail mail;

public Mail Mail
{
get { return mail; }
set { mail = value; }
}

public void Handle(Request request)
{
LogDown();

if (request == Request.SendMail)
{
new SendMailCommand().Handle(mail);
}
else if(request == Request.ReceiveMail)
{
new ReceiveMailCommand().Handle(mail);
}
else if (request == Request.ForwardMail)
{
new ForwardMailCommand().Handle(mail);
}
else if (request == Request.ReplyMail)
{
new ReplyMailCommand().Handle(mail);
}
}

public class SendMailCommand
{
public void Handle(Mail mail)
{
Console.WriteLine(string.Format("Send Mail To : {0}", mail.Receiver));
}
}

public class ReplyMailCommand
{
public void Handle(Mail mail)
{
Console.WriteLine(string.Format("Reply {0}'s mail on Date:{1}", mail.Sender, mail.Date));
}
}

public class ForwardMailCommand
{
public void Handle(Mail mail)
{
Console.WriteLine(string.Format("Forward {0}'s mail to {1} ", mail.Sender, mail.Receiver));
}
}

public class ReceiveMailCommand
{
public void Handle(Mail mail)
{
Console.WriteLine(string.Format("Receive Mail From:{0}", mail.Sender));
}
}

4.最后的重构:

public class MailSystem
{
private Mail mail;

public Mail Mail
{
get { return mail; }
set { mail = value; }
}

private Hashtable cmdList = new Hashtable();

public MailSystem()
{
InitCommand();
}

private void InitCommand()
{
cmdList.Add(Request.ForwardMail,new ForwardMailCommand());
cmdList.Add(Request.ReceiveMail, new ReceiveMailCommand());
cmdList.Add(Request.ReplyMail, new ReplyMailCommand());
cmdList.Add(Request.SendMail, new SendMailCommand());
}

public void Handle(Request request)
{
LogDown();
((ICommand)cmdList[request]).Handle(mail);
}

public interface ICommand
{
void Handle(Mail mail);
}

public class SendMailCommand:ICommand
{
public void Handle(Mail mail)
{
Console.WriteLine(string.Format("Send Mail To : {0}", mail.Receiver));
}
}

public class ReplyMailCommand:ICommand
{
public void Handle(Mail mail)
{
Console.WriteLine(string.Format("Reply {0}'s mail on Date:{1}", mail.Sender, mail.Date));
}
}

public class ForwardMailCommand:ICommand
{
public void Handle(Mail mail)
{
Console.WriteLine(string.Format("Forward {0}'s mail to {1} ", mail.Sender, mail.Receiver));
}
}

public class ReceiveMailCommand:ICommand
{
public void Handle(Mail mail)
{
Console.WriteLine(string.Format("Receive Mail From:{0}", mail.Sender));
}
}

5.Client:

public class Client
{
public static void Main()
{
MailSystem sys = new MailSystem();
sys.Mail = new Mail("flyingmain@gmail.com", "f.chen@cleversoft.com", DateTime.Now.Date, "Happy new year !");
sys.Handle(Request.SendMail);
Console.WriteLine("==================================================================");
sys.Handle(Request.ForwardMail);
Console.WriteLine("==================================================================");
sys.Handle(Request.ReceiveMail);
Console.WriteLine("==================================================================");
sys.Handle(Request.ReplyMail);
Console.Read();
}
}

转载于:https://www.cnblogs.com/flyingchen/archive/2007/02/05/641290.html