乐在其中设计模式(C#) - 解释器模式(Interpreter Pattern)

2022-04-30 07:51:23

作者：webabcd

介绍
给定一个语言, 定义它的文法的一种表示，并定义一个解释器，该解释器使用该表示来解释语言中的句子。

示例
有一个Message实体类，某个类对它的操作有Get()方法。现在要求用具有某一规则的中文语法来执行这个操作。

MessageModel

using System;

using System.Collections.Generic;

using System.Text;

namespace Pattern.Interpreter

{

/// <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.Interpreter

{

/// <summary>

/// Sql方式操作Message

/// </summary>

public class SqlMessage

{

/// <summary>

/// 获取Message

/// </summary>

/// <returns></returns>

public static List<MessageModel> Get()

{

List<MessageModel> l = new List<MessageModel>();

l.Add(new MessageModel("SQL方式获取Message", DateTime.Now));

return l;

}

Context

using System;

using System.Collections.Generic;

using System.Text;

namespace Pattern.Interpreter

{

/// <summary>

/// Context

/// </summary>

public class Context

{

private string _input;

private string _output;

/// <summary>

/// 构造函数

/// </summary>

/// <param name="input">输入内容</param>

public Context(string input)

{

this._input = input;

}

/// <summary>

/// 输入内容

/// </summary>

public string Input

{

get { return _input; }

set { _input = value; }

}

/// <summary>

/// 输出内容

/// </summary>

public string Output

{

get { return _output; }

set { _output = value; }

}

AbstractExpression

using System;

using System.Collections.Generic;

using System.Text;

namespace Pattern.Interpreter

{

/// <summary>

/// 抽象公式（AbstractExpression）

/// </summary>

public abstract class AbstractExpression

{

/// <summary>

/// 解释Context的方法

/// </summary>

/// <param name="context">context</param>

public void Interpret(Context context)

{

if (String.IsNullOrEmpty(context.Input))

{

return;

}

context.Output += GetCSharp(context.Input);

}

/// <summary>

/// 获得输入内容所对应的C#代码

/// </summary>

/// <param name="source">source</param>

/// <returns></returns>

private string GetCSharp(string source)

{

string csharp = "";

string word = "";

// 从输入内容中取得要解释的词

word = GetWord(source);

// 从字典中找到word所对应的C#代码

GetDictionary().TryGetValue(word, out csharp);

return csharp;

}

/// <summary>

/// 从输入内容中取得要解释的词

/// </summary>

/// <param name="source">source</param>

/// <returns></returns>

public abstract string GetWord(string source);

/// <summary>

/// 获取字典

/// </summary>

/// <returns></returns>

public abstract Dictionary<string, string> GetDictionary();

}

DatabaseExpression

using System;

using System.Collections.Generic;

using System.Text;

using System.Text.RegularExpressions;

namespace Pattern.Interpreter

{

/// <summary>

/// 终端公式（TerminalExpression）分析与数据库相关的

/// </summary>

public class DatabaseExpression : AbstractExpression

{

/// <summary>

/// 从输入内容中取得要解释的词

/// </summary>

/// <param name="source">source</param>

/// <returns></returns>

public override string GetWord(string source)

{

MatchCollection mc;

Regex r = new Regex(@"\{(.*)\}");

mc = r.Matches(source);

return mc[0].Groups[1].Value;

}

/// <summary>

/// 获取与数据库相关的字典

/// </summary>

/// <returns></returns>

public override Dictionary<string, string> GetDictionary()

{

Dictionary<string, string> d = new Dictionary<string, string>();

d.Add("数据库", "Sql");

return d;

}

ObjectExpression

using System;

using System.Collections.Generic;

using System.Text;

using System.Text.RegularExpressions;

namespace Pattern.Interpreter

{

/// <summary>

/// 终端公式（TerminalExpression）分析与对象相关的

/// </summary>

public class ObjectExpression : AbstractExpression

{

/// <summary>

/// 从输入内容中取得要解释的词

/// </summary>

/// <param name="source">source</param>

/// <returns></returns>

public override string GetWord(string source)

{

MatchCollection mc;

Regex r = new Regex(@"\[(.*)\]");

mc = r.Matches(source);

return mc[0].Groups[1].Value;

}

/// <summary>

/// 获取与对象相关的字典

/// </summary>

/// <returns></returns>

public override Dictionary<string, string> GetDictionary()

{

Dictionary<string, string> d = new Dictionary<string, string>();

d.Add("信息", "Message");

return d;

}

MethodExpression

using System;

using System.Collections.Generic;

using System.Text;

using System.Text.RegularExpressions;

namespace Pattern.Interpreter

{

/// <summary>

/// 终端公式（TerminalExpression）分析与方法相关的

/// </summary>

public class MethodExpression : AbstractExpression

{

/// <summary>

/// 从输入内容中取得要解释的词

/// </summary>

/// <param name="source">source</param>

/// <returns></returns>

public override string GetWord(string source)

{

MatchCollection mc;

Regex r = new Regex(@"\((.*)\)");

mc = r.Matches(source);

return mc[0].Groups[1].Value;

}

/// <summary>

/// 获取与方法相关的字典

/// </summary>

/// <returns></returns>

public override Dictionary<string, string> GetDictionary()

{

Dictionary<string, string> d = new Dictionary<string, string>();

d.Add("获取", ".Get()");

return d;

}

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 Microsoft.CSharp;

using System.Reflection;

using System.Text;

using System.Collections.Generic;

using Pattern.Interpreter;

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

{

protected void Page_Load(object sender, EventArgs e)

{

string chinese = "{数据库}[信息](获取)";

Context context = new Context(chinese);

List<AbstractExpression> l = new List<AbstractExpression>();

l.Add(new DatabaseExpression());

l.Add(new ObjectExpression());

l.Add(new MethodExpression());

foreach (AbstractExpression exp in l)

{

exp.Interpret(context);

}

Assembly assembly = Assembly.Load("Pattern.Interpreter");

MethodInfo method = assembly.GetType("Pattern.Interpreter." + context.Output.Split('.')[0]).GetMethod(context.Output.Split('.')[1].Replace("()", ""));

object obj = method.Invoke(null, null);

List<MessageModel> m = (List<MessageModel>)obj;

Response.Write("中文语法：" + chinese);

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

Response.Write("解释后的C#代码：" + context.Output);

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

Response.Write("执行结果：" + m[0].Message + " " + m[0].PublishTime.ToString());

}

运行结果
中文语法：{数据库}[信息](获取)
解释后的C#代码：SqlMessage.Get()
执行结果：SQL方式获取Message 2007-5-1 8:48:07

参考
http://www.dofactory.com/Patterns/PatternInterpreter.aspx

OK
[源码下载]

本文转自webabcd 51CTO博客，原文链接：http://blog.51cto.com/webabcd/344555，如需转载请自行联系原作者

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