Event handling in GXT-GWT

This is the way I like to handle events. Note the ease with which the MessageSenders and MessageListeners can be "weaved" using aop/annotations. Unfortunately, I am not going the aop way for the time being.

The big picture:

Architecture diagram of a GWT-GXT application

Using a message listener

Using a message sender

The SubmitButtonListener is a button listener. I tend to separate UI events from business/semantic events. The message sender is used to fire the event. There is another reason why this separation was required, GWT EventHandler code cannot register listeners, while a event is being processed. I re-wrote the custom code and wanted to use it only for semantic events.