public abstract class BaseInputLog : IDisposable
    {
        protected System.IO.StreamReader file;

        public BaseInputLog()
        {
            this.LoadFile();
        }

        protected abstract void LoadFile();

        public string ReadLine()
        {
            return this.file.ReadLine();
        }

        public int Peek()
        {
            return this.file.Peek();
        }

        public void Close()
        {
            this.file.Close();
        }

        public void Dispose()
        {
            this.file.Dispose();
        }
    }

    public class InputLogFileSystem : BaseInputLog
    {
        private readonly string filePath;
        public InputLogFileSystem(string path) : base()
        {
            this.filePath = path;
        }

        protected override void LoadFile()
        {
            this.file = new System.IO.StreamReader(this.filePath);
        }
    }

    public class InputLogFTP : BaseInputLog
    {

        private readonly string uri;
        private readonly string user;
        private readonly int port;
        private readonly string password;
        public InputLogFTP(string uri) : base()
        {
            this.uri      = uri;
            this.user     = string.Empty;
            this.port     = 22;
            this.password = string.Empty;
        }

        public InputLogFTP(string uri, int port, string user, string password) : base()
        {
            this.uri = uri;
            this.user = user;
            this.port = port;
            this.password = password;
        }

        protected override void LoadFile()
        {
            string localFilePath = string.Empty;
            //localFilePath = downloaded from ftp
            this.file = new System.IO.StreamReader(localFilePath);
        }
    }