How to control access to a network share listed as a context in Tomcat?

[echocoder]

I have an instance of Tomcat 7.0.32 installed. The server.xml is configured to use clientAuth="want" in the Connector. I have a Context that has a docBase set to be a network share. This particular Context I want the user to be authenticated before they can access it, otherwise I want them redirected to an error page. I have tried setting security constraints, filters and valves, but I am not sure I am doing it correctly. Could someone tell me the easiest / most efficient way to achieve the above access control to a context? Authenticated users would have the username in the session variable, so user accounts are not directly tied to the tomcat-users.xml file.