学步园

namespace SEI.DL88250.SourceCodes.CSharp.QTL
{        
    /// <summary>查询系统类
    /// </summary>
    public class QTL
    {
        /// <summary>文本缓冲区
        /// </summary>
        internal static ArrayList textContentBuffer;
        /// <summary>查询结果集，行号集合
        /// </summary>
        private ArrayList _queryResult;    
        /// <summary>表达式分析器
        /// </summary>
        private ExpressionAnalyser _ea;
        
        /// <summary>构造器，初始化文本集
        /// </summary>
        public QTL()
        {
            textContentBuffer = new ArrayList();
            textContentBuffer.Add(null);        // 填掉第0个位置
            _queryResult = new ArrayList();
        }

        /// <summary>清空查询结果
        /// </summary>
        public void ClearResults()
        {
            _queryResult.Clear();
        }

        /// <summary>清屏
        /// </summary>
        public void ClearScreen()
        {
            Console.ReadLine();
            Console.Clear();
        }

        /// <summary>让用户输入查询字串，并开始分析
        /// </summary>
        public void UserInputQuery()
        {
            Console.Write("Please enter a query or 'q' to Quit: ");
            string query = Console.ReadLine();
            if ("q" == query)
            {
                Environment.Exit(0);
            }
            _ea = new ExpressionAnalyser(query);
        }

        /// <summary>根据用户输入的字串进行查询处理
        /// </summary>
        public void ProcessQuery()
        {
            ArrayList expression = _ea.ToPostfix();        // 后缀表达式集
            #region 后缀表达式正确性验证显示测试
            //IEnumerator ie = expression.GetEnumerator();
            //while (ie.MoveNext())
            //{
            //    Console.Write(((Expression)ie.Current).ExpressionString);
            //}
            //Console.WriteLine();
            #endregion 正确性验证显示结束
            Stack s = new Stack();                // 运算过程栈
            Stack p = new Stack();                // 运算字串栈，用于分步打印
            
            #region 基于后缀表达式进行查询运算与结果分步显示
            for (int i = 0; i < expression.Count; i++)
            {
                Expression exp = (Expression)expression[i];
                switch (exp.ExpressionType)
                { 
                    case "query":
                    {
                        s.Push(new UnitaryQuery(exp.ExpressionString));
                        #region 打印当前关键字运算的结果
                        string curExp = exp.ExpressionString;
                        p.Push((object)curExp);
                        PrintSetpResult(curExp, s);
                        #endregion 打印结束
                        break;
                    }
                    case "&&":
                    {
                        Query q1 = (Query)s.Pop();
                        Query q2 = (Query)s.Pop();
                        s.Push(new AndQuery(q1, q2));
                        #region 打印当前"&&"运算的结果
                        string curExp = "";
                        curExp += (string)p.Pop();
                        curExp += " && ";
                        curExp += (string)p.Pop();
                        p.Push((object)(curExp));
                        PrintSetpResult(curExp, s);
                        #endregion 打印结束
                        break;
                    }
                    case "||":
                    {
                        Query q1 = (Query)s.Pop();
                        Query q2 = (Query)s.Pop();
                        s.Push(new OrQuery(q1, q2));
                        #region 打印当前"||"运算的结果
                        string curExp = "";
                        curExp += (string)p.Pop();
                        curExp += " || ";
                        curExp += (string)p.Pop();
                        //curExp = curExp.Insert(curExp.Length, ")");
                        p.Push((object)(curExp));
                        PrintSetpResult(curExp, s);
                        #endregion 打印结束
                        break;
                    }
                case "!":
                    {
                        Query q = (Query)s.Pop();
                        s.Push(new NotQuery(q));
                        #region 打印当前"!"运算的结果
                        string curExp = "!";
                        curExp += (string)p.Pop();
                        p.Push((object)(curExp));
                        PrintSetpResult(curExp, s);
                        #endregion 打印结束
                        break;
                    }
                    default:
                        Console.Error.WriteLine("Expression error!");
                        break;
                }
            }
            #endregion 核心运算完毕
            #region 将结果转换成整型行号数组
            for (int i = 0; i < ((Query)s.Peek()).Solution.Count; i++)
            {
                _queryResult.Add(Convert.ToInt32(((Query)s.Peek()).Solution[i].ToString()));
            }
            #endregion
        }

        /// <summary>打印运算过程中的分步结果概要
        /// </summary>
        /// <param name="curExp">当前表达式字串</param>
        /// <param name="s">表达式栈</param>
        private void PrintSetpResult(string curExp, Stack s)
        {
            Console.WriteLine(curExp);
            Console.Write("        " + ((Query)s.Peek()).Solution.Count + " line(s) math ");
            for (int j = 0; j < ((Query)s.Peek()).Solution.Count; j++)
            {
                Console.Write(" [{0}] ", ((Query)s.Peek()).Solution[j]);
            }
            Console.WriteLine();    
        }

        /// <summary>打印结果的详细情况
        /// </summary>
        public void PrintResultDetails()
        {
            IEnumerator e = _queryResult.GetEnumerator();
            while (e.MoveNext())
            {
                Console.WriteLine("[{0}]: {1}",
                    e.Current.ToString(), textContentBuffer[Convert.ToInt32(e.Current.ToString())].ToString());
            }
        }

        /// <summary>读取一个查询文本
        /// </summary>
        public void AddFile()
        {
            string fileName = "Test.txt";
            StreamReader fReader = File.OpenText(fileName);
            Console.WriteLine("Reading " + fileName + " -- please wait!");
            string aLine = fReader.ReadLine();
            for (int i = 1; null != aLine; i++)
            {
                textContentBuffer.Add((object)(aLine));
                aLine = fReader.ReadLine();
            }
            Console.WriteLine("Reading " + fileName + " -- OK, done!");
            Console.WriteLine("The text file " + new FileInfo(fileName).Name + ' '
                + "         contains " + textContentBuffer.Count
                + " lines in " + new FileInfo(fileName).Length + " bytes.");
        }
    }
}