httpOnly filter in Groovy

I was able to make the httpOnly filter work in Groovy - the idea was really appealing to me. However, it turns out that it doesn't syntactically save just a whole lot of effort. While groovy has duck-typing, it doesn't get pushed down to Java, so you still have to type everything within the Filter. Furthermore, because it has to be recognized when the app loads, not dynamically, you still have the same compile/reload cycle as you do with a filter written in Java. The only syntactical advantage (that I've seen so far) is being able to short-circuit some of the tests because of "the Groovy truth" and when rendering, you get to use GStrings instead of .append over and over.

So there you have it - it's not that much cleaner to implement the filter in Groovy. I'll have to check the Grails API to see if they pass you a true HTTPServletResponse, or if there's any possibility of wrapping the response that gets injected into controllers to make the cookie re-writing simpler.