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

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

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; 

                /// Message内容 

                public string Message 

                        get { return _message; } 

                        set { _message = value; } 

                private DateTime _publishTime; 

                /// Message发布时间 

                public DateTime PublishTime 

                        get { return _publishTime; } 

                        set { _publishTime = value; } 

        } 

}

SqlMessage

        /// Sql方式操作Message 

        public class SqlMessage 

                /// 获取Message 

                /// <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

        /// Context 

        public class Context 

                private string _input; 

                private string _output; 

                /// <param name="input">输入内容</param> 

                public Context(string input) 

                        this._input = input; 

                /// 输入内容 

                public string Input 

                        get { return _input; } 

                        set { _input = value; } 

                /// 输出内容 

                public string Output 

                        get { return _output; } 

                        set { _output = value; } 

AbstractExpression

        /// 抽象公式（AbstractExpression） 

        public abstract class AbstractExpression 

                /// 解释Context的方法 

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

                public void Interpret(Context context) 

                        if (String.IsNullOrEmpty(context.Input)) 

                        { 

                                return; 

                        } 

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

                /// 获得输入内容所对应的C#代码 

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

                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; 

                /// 从输入内容中取得要解释的词 

                public abstract string GetWord(string source); 

                /// 获取字典 

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

DatabaseExpression

using System.Text.RegularExpressions; 

        /// 终端公式（TerminalExpression）分析与数据库相关的 

        public class DatabaseExpression : AbstractExpression 

                public override string GetWord(string source) 

                        MatchCollection mc; 

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

                        mc = r.Matches(source); 

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

                /// 获取与数据库相关的字典 

                public override Dictionary<string, string> GetDictionary() 

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

                        d.Add("数据库", "Sql"); 

                        return d; 

ObjectExpression

        /// 终端公式（TerminalExpression）分析与对象相关的 

        public class ObjectExpression : AbstractExpression 

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

                /// 获取与对象相关的字典 

                        d.Add("信息", "Message"); 

MethodExpression

        /// 终端公式（TerminalExpression）分析与方法相关的 

        public class MethodExpression : AbstractExpression 

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

                /// 获取与方法相关的字典 

                        d.Add("获取", ".Get()"); 

client

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 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("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

<a href="http://www.dofactory.com/Patterns/PatternInterpreter.aspx" target="_blank">http://www.dofactory.com/Patterns/PatternInterpreter.aspx</a>

OK

<a href="http://down.51cto.com/data/100859" target="_blank">[源码下载]</a>

     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