Dont want to use default user authentication but want roles

[Janis Olex]

Hi, dudes!
Finally I found somebody doing same crazy stuff I do (developing in JAVA)
I have one problem (ambition)!
I don't understand quite how does user stuff is managed during default servlet engine?
I mean! I don't want do all this default user authentication, tomcat-users.xml and web.xml configuration. But I still want HttpServlet.isUserInRole() to use!
So how do my servlet can set up roles (read by my application from very secure Mysql DB) in such a way that Struts 1.1. and Servlet engine becomes aware of them!
Mostly I need Struts-tiles and struts-logic to use them to show/hide different parts of the application!
Thanks