设计模式 - Interpreter Pattern(解释器模式)
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
