Event passing in (Swing) GUI Application

Hi,

I'm build a GUI app using Swing. I want to have it be as modular as
possible for all the usual reasons including reuse of common
components.

Some of my componets are GUI panels, some are non-GUI classes.

I'm a little confused as to the best way to communicate between
components though. When I use a Swing Jxxx widget I can register
EventListeners and FocusListeners etc. What sort of event mechanism
should I be using to talk between my higher level application
components?

I've gone with use PropertyChangeEvents for now should I be used custom
events though?

Or is this all down to my own design. I guess I'm asking for "What, if
any, is the usual event mechanism between GUI/non-GUI objects?"

Anyone got any good resources online?

.