Welcome to Gracelets. If you use JSF/Facelets technology or are considering it as a view technology and at the same time would like to have the power of groovy while you develop pages, controllers and prototypes, Gracelets could well be the solution you are looking for.
Gracelets is the fusion of two mainstream technologies, Groovy + Facelets/JSF. It allows Groovy scripts to be used instead of XHTML/JSP views, Facelet tag libraries and JSF component libraries. Gracelets has also been described as a DSL (Domain-Specific Langage) for JSF/Facelets.
Gracelets has the goal of facilitating development of web based applications using the Java Server Faces framework. It allows one to use many Groovy language features (like closures) as complements and/or replacements for some JSF/Facelets features (like EL) that can become very cumbersome and restrictive in many scenarios.