/// <summary>
        /// Private constructor called when the singleton instance is
        /// created.
        /// </summary>
        private SessionController()
        {
            RegistrySessionStorageImpl regSSI = new RegistrySessionStorageImpl();

            sessionProvider       = regSSI;
            regExportProvider     = regSSI;
            sessionAttribProvider = regSSI;
            csvExportProvider     = new CsvSessionExportImpl();

            invalidateSessionList(this, true);
        }
        /// <summary>
        /// Private constructor called when the singleton instance is 
        /// created.
        /// </summary>
        private SessionController()
        {
            RegistrySessionStorageImpl regSSI = new RegistrySessionStorageImpl();
            sessionProvider = regSSI;
            regExportProvider = regSSI;
            sessionAttribProvider = regSSI;
            csvExportProvider = new CsvSessionExportImpl();

            invalidateSessionList(this, true);
        }