Question

I want to write communication interface via serial port. (using Qt)

I have QSerialPort class, which provides interface to work with serial port.
I inherited QMySerialPort from QSerialPort class, which added some functionality and dialog window to config port.

Now I want to write 2 protocol classes:
First – low layer class, sendPacket, parseData methods and etc..
Second – high layer: setDeviceID, getDeviceID, onPayload, etc..

How can I do it?
The first thing that comes to mind is create some QSerialInterface meta-class, which will include the objects of QMySerialPort and 2 protocol layers classes.
And I should implement some connection between them.

Such as:

Protocol class:
void setPort(QSerialPort *port) { m_port = port; }

sendPacket method:
m_port->send(local_data);

But I think this approach is wretched.
Do you have any ideas?
Maybe I should use design patterns here?

Answer 1

Maybe you should narrow down the scope of your question to get a more useful answer. That said, there are a couple of things I’d like to point out.

• Try to keep your UI code separate from your business logic. More specifically, the code for the configuration dialog has no place in QMySerialPort.
• Depending on the kind of functionality you’re adding over QSerialPort, keep in mind that you can use QSerialPort through composition instead of inheritance, and in many cases (if not most) the former is preferable.
• In general, try to define the responsibility for each interface/class as narrow and focused as possible. Parsing data should go in a separate interface from sending/receiving individual packets. This way you can substitute different communication mediums while keeping the overall protocol and the objects that deal with it unchanged.
• The setPort method is OK, although I personally would pass port as parameter to the constructor instead.