SECURITY WARNING: Please take note of the warning at the end of the tutorial !
UPDATE 2011-07-08: A good article on the security concern I recommend http://www.jroller.com/melix/entry/customizing_groovy_compilation_process
We use the Groovy Script Engine to run small Groovy scripts to prepare incoming interface messages for further processing. Here I share with you how to embed the engine into a ZK page. Very basic, though it shows you the concept and it is wasy to expand to your needs.