What are your best Swing design patterns and tips? [closed]

Answer 1

You're not supposed to extend JFrame, JDialog, JPanel, JButton, Janything classes (although certain extensions to table behaviour are only available if you extend it). You can extend JComponent if you feel like doing custom component. If are supposed to implement models (e.g. by extending abstract models), listeners (e.g. by extending adapters), but that's it. You don't need/have to extend swing components usually, and you better not do it, as it makes your code tied to implementation of superclass.

Answer 2

I think that the main problem you are going to be faced with is testability of your gui application.

So regarding maintainability and ease of unit testing I am leaning towards the "Presenter first" idiom instead of Model View Controller (MVC) and other derivatives that instruct you to have the view knowing of the actual application logic (Model). The best resource is the web site of the group that introduced it as a thought.

Since using an approach like that is going to take a lot of boilerplate code to initialize the various elements of your application I would also suggest in using a dependency injection framework. I have settled with Guice.

Answer 3

Avoid inherit when composition would be easier.

For instance I have seen a lot like this:

public class CustomerSupportApp extends JFrame { 
     JList<Customer> customers;
     OtherBusinessComponent importantComponent;

     etc. etc

}

This is mixing business logic with presentation. It only makes changes from difficult to impossible.

Better is:

public class CustomerSupportApp { 
     JList<Customer> customers;
     OtherBusinessComponent importantComponent;
     // The app HAS-A frame but not IS-A frame
     JFrame frame;
     etc. etc
}

Answer 4

Definitely put the GUI in one class and the logic in another class or multiple classes -- to the greatest extent possible. If you use the MVC (Model-View-Controller) pattern, this will happen automatically. If you don't do this, the GUI will quickly become unmaintainably complicated.