Siteminder integration with Acegi

[pgarvey]

Acegi requires a "j_acegi_security_check" URL to attempt authentication. Normally it gets the "j_acegi_security_check" from the login page post along
with the username and password. If Siteminder only send Acegi the username in the request header how does it attempt authentication is no "j_acegi_security_check" is present? Based on the current SiteminderAuthenticationProcessingFilte class authentication would never occur with Siteminder. To get it to work I had to derive a class from SiteminderAuthenticationProcessingFilte and override the requiresAuthentication() method which is found on the grandparent
of the SiteminderAuthenticationProcessingFilter class the abstractProcessingFilter class.

[smccrory]

Added as JIRA #217:
http://opensource2.atlassian.com/projects/spring/browse/SEC-217

[smccrory]

Paul's solution code has been committed to SVN. Unit tests confirmed passing. I'll try to perform integration testing in an actual environment within the next week. Others please do the same and let me know your results!

Thanks, Scott