Exception used raise an access control violation. This exception has the
web - the web which was being accessed
topic - the topic being accessed (if any)
user - canonical username of the person doing the accessing. Use the methods of the TWiki::Users class to get more information about the user.
mode - the access mode e.g. CHANGE, VIEW etc
reason a text string giving the reason for the refusal.
The exception may be thrown by plugins. If a plugin throws the exception, it
will normally be caught and the browser redirected to a login screen (if the
user is not logged in) or reported (if they are and just don't have access).
ClassMethod new ($mode,$user,$web,$topic,$reason)
$mode - mode of access (view, change etc)
$user - canonical user name of user doing the accessing
$web - web being accessed
$topic - topic being accessed
$reason - string reason for failure
All the above fields are accessible from the object in a catch clause
in the usual way e.g.
Generate a summary string. This is mainly for debugging.