sfBasicSecurityFilter:
sfBasicSecurityFilter checks security by calling the getCredential() method
of the action. Once the credential has been acquired,
sfBasicSecurityFilter verifies the user has the same credential by calling
the hasCredential() method of SecurityUser.
sfCacheFilter:
sfCacheFilter deals with page caching and action caching.
sfCommonFilter:
sfCommonFilter automatically adds javascripts and stylesheets information
in the sfResponse content.
sfExecutionFilter:
sfExecutionFilter is the last filter registered for each filter chain. This
filter does all action and view execution.