The module is "posts" and the action is "list" and there is only one argument between the action and the .page servlet extension. So, the urlPattern that is used is posts.list.1. Since the ServletRequest is wrapped in an ActionServletRequest class, the "4159" part of the url can be retrieved by code like:
int topicId = this.request.getIntParameter("topic_id");
FWIW, this also defines the parameter tags to use if you want to use the older parameter syntax. E.g.:
Thanks for the quick reply, that was impressive. Your comments pretty much confirm what I was understanding from looking through the code.
Actually, the comments in the code were also very helpful in piecing it all together, so if anyone else is confused like I was I would suggest looking there. The net.jforum.UrlPattern class has some particularly useful info regarding how the modules, actions, and urlPatterns all tie together. [originally posted on jforum.net by marlingj]