[Building Sakai] Adding a refresh user cache to AuthzGroupService - patch for review

[Stephen Marquard]

Hi all,

If you have a group provider (CM or other), you may be interested in the performance effects of multiple user logins for the same user in quick succession, e.g. as happens wih WebDav (http://jira.sakaiproject.org/jira/browse/SAK-11636 )

To mitigate the effects of this, I'm proposing to add a cache to refreshUser in AuthzGroupService with a default TTL of 120 seconds:

http://jira.sakaiproject.org/jira/browse/KNL-181

There is a patch attached for review based on work by Matthew Buckett:

 http://jira.sakaiproject.org/jira/secure/attachment/18015/KNL-181.diff

It is fairly simple and should also work in 2-5-x.

If you have any comments or concerns before I commit this, please add them to the JIRA.

Regards
Stephen