What is the Swing-equivalent to HTML

Answer 1

I don't believe that there is one simple way of doing this, but there is a way to do it.

I would implement a data model class that indicates the grouping that you've describe above. Place instances of those data models in your javax.swing.ComboBoxModel implementation instance.

You can then implement a javax.swing.ListCellRenderer to format the output as you like with indents for the text data. You may just want to extend the javax.swing.DefaultListCellRenderer or possibly borrow its implementation wholesale from the Java source.

As for the L&F you should be able to stay within normal guidelines by using the above methods and you won't have to fight with figuring out how to implement it. Look at the default Swing components they will provide a lot of insight in to how to deal with L&F.

Additionally, I think there are mechanisms (you'll have to forgive me, it's been YEARS since I've done full Swing development) to allow you to determine if an item is selectable or not.