code: void rollback()
  	{
  		switch (data_type)
  		{
  		case Tango_DEV_BOOLEAN :
  			bool_val = old_bool_val;
  			break;
  		
  		case Tango_DEV_SHORT :
  			short_val = old_short_val;
  			break;
  		
  		case Tango_DEV_LONG :
  			long_val = old_long_val;
  			break;
  		
  		case Tango_DEV_LONG64 :
  			long64_val = old_long64_val;
  			break;
  		
  		case Tango_DEV_DOUBLE :
  			double_val = old_double_val;
  			break;
  		
  		case Tango_DEV_STRING :
  			str_val = old_str_val;
  			break;
  		}
  	}
docs: --------------------------------------------------------------------------