I know how to map users to roles via tomcat-users.xml, and also how to
deny access to particular servlets in this way.  However, what I'd
like to do is be able to, programmatically, from within the servlet,
perform different actions based on what roles the current user has
been assigned.  ( Specifically, I want to display a "delete" button on
the webpage iff an "admin" role has been granted. )

Any way to do this?  If not, any workaround for checking for the user
name directly?  ( although this is a substandard hack )

Thanks,

Isaac