A Java/Groovy API to generate Groovy source files

I'm looking for a Java or Groovy library to generate Groovy classes source files. I've CodeModel and this post but they are for Java.

Basically, I'd like to generate a Groovy class programmatically knowing the class name, the class attributes and generate particular methods depending on the class attributes.

I know Groovy templates, but there might be other ways.

Thanks