Using Tomcat 4 Security Realms
Subject:   can also be done by a security filter
Date:   2003-08-07 06:19:54
From:   anonymous2
For those that needs a bit more control of how authentication is done, and how it interacts with the application can look at, which implements the same functionality by using servlet filters. We use this because we need more control with how FROM authentication is done, eg. by including a login page on all content pages.