I'm looking for a template engine. Requirements:

• Runs on a JVM. Java is good; Jython, JRuby and the like, too...
• Can be used outside of servlets (unlike JSP)
• Is flexible wrt. to where the templates are stored (JSP and a lot of people require the templates to be stored in the FS). It should provide a template loading interface which one can implement or something like that
• Easy inclusion of parameterized templates- I really like JSP's tag fragments
• Good docs, nice code, etc., the usual suspects

I've looked at JSP- it's nearly perfect except for the servlet and filesystem coupling, Stringtemplate- I love the template syntax, but it fails on the filesystem coupling, the documentation is lacking and template groups and stuff are confusing, GXP, TAL, etc.

Ideas, thoughts?

Alex