A role-based authorization filter which takes four parameters:
authnServiceBean - The Spring-configured authentication service
authzServiceBean - The Spring-configured authorization service
role - A string describing which role is required to access this resource
selectGradebookRedirect - Where to go if a gradebook doesn't seem to have
been selected yet; this can happen on an application redeploy to Tomcat,
since JSF beans will be lost but authentication for the session might
still be active
Because Tomcat 5.* developers decided to take an eccentric interpretation of the
ambiguous language in the Servlet specification, Tomcat doesn't accept the
combination of directories and wildcards for the "url-pattern" of the
filter mapping.