ConsoleEngineBase.cs

using System;
using System.IO;

namespace Utils
{
    public abstract class ConsoleEngineBase
    {
        private string[] m_args;
        protected bool ReadInput = true;
        protected System.IO.TextReader In = null;
        protected System.IO.TextWriter Out = null;
        protected System.IO.TextWriter Error = null;

        public ConsoleEngineBase()
        {
            //by default, read from/write to standard streams
            this.In = System.Console.In;
            this.Out = System.Console.Out;
            this.Error = System.Console.Error;
        }

        public void Main(string[] args)
        {
            this.m_args = args;

            if (this.ValidateArguments())
            {
                this.PreProcess();
                if (this.ReadInput)
                {
                    string currentLine = this.In.ReadLine();
                    while (currentLine != null)
                    {
                        this.ProcessLine(currentLine.Trim());
                        if(this.In.Peek() == -1) break;
                        currentLine = this.In.ReadLine();
                    }
                }
                this.PostProcess();
            }
            else
                this.Error.Write("Usage: " + this.Usage());
        }

        public void Main(string[] args,
            System.IO.TextReader In,
            System.IO.TextWriter Out,
            System.IO.TextWriter Error)
        {
            //this version of Main allows alternate streams
            this.In = In;
            this.Out = Out;
            this.Error = Error;
            this.Main(args);
        }

        protected virtual bool ValidateArguments()
        {
            //override this to add custom argument checking
            return true;
        }

        protected virtual string Usage()
        {
            //override this to add custom usage statement 
            return "";
        }

        protected virtual void PreProcess()
        {
            //override this to add custom logic that 
            //executes just before standard in is processed
            return;
        }

        protected virtual void PostProcess()
        {
            //override this to add custom logic that 
            //executes just after standard in is processed
            return;
        }

        protected virtual void ProcessLine(string line)
        {
            //override this to add custom processing 
            //on each line of input
            return;
        }

        protected string[] Arguments
        {
            get { return this.m_args; }
        }
    }
}