This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
You wouldn't be able to do this for a specific action. Whatever extension you might want to use would be applied to all of the Controller's actions. This is handled via the Controller's configuration file.