Question

I just stared looking into Poco framework. I have another underlying framework that already was using Poco framework and abstracting some parts of it to make it even more easier.

I want to explain the problem with a simple scenario:
Consider that I have a rectangle shape object in my program. The shape has private hit Testing methods inside to it and on hit testing being true for a certain time, I had to fire a function in another class i.e my Fountain class.

I don’t need to pass any specific object information of shape to the function in the Fountation class. My framework already gives me some functionaliy of NotifyEvent and AddListener. If I would have gone by this approach, I would have an event inside my shape class which would be subscribed in fountain by Add Listener (object if shape is passed) and the event notified from within the shape class.

Now, with the Poco notification center, instead of passing the shape object reference to foundation class, I’ll be passing the NotificationCenter reference to the second class. The fountain class will then have an observer and the observer will be notified from shape by postNotification()
The only difference that I see here between the two approaches is not passing the specific object information.
I am just a fresher dev here trying to learn good coding practices whenever possible, and not clear about the decoupling here. How are the two classes decoupled here? (because I am not passing shape object and just using notificationcenter object?)

EDIT: Adding to the above question. Let’s say I have 10 other classes which have to listen to a certain notification, so I’ll have to pass the reference of the Notification Center to all these classes as well? That way only I’ll be able to add an observer for the notification center in my classes.

Answer 1

Basically yes. If the Fountain class only knows about the NotificationCenter, then it is not coupled to the shape (Rectangle or others) anymore. This assumes that the notification posted by the shapes is also not dependent on the object that fires it.

Edit: The reply to your edit is yes, you’ll need to call the addObserver method with each object that needs notifications