He used a "@ajaxaction" marker in a previous article to implement the Ajax requests, but with other tools there could be an issue with the response. To help with this, he's worked up a handler to detect what needs to be done with the response. He applies this to create the authentication system, making it easy to include a simple ACL method into his application.

He includes code examples for the Controller to handle the detection, how to implement it, and the class to work with those "doclet" markers for the Ajax actions.