How to get all logged in Subjects

[Alex Orlov]

Hi all,
 
Could anyone say, how I can to get all logged in subjects. For example, Subjects
have roles, roles have permissions. If in application a role were modified 
dynamically
(for example in DB), I want to get all logged in subjects, iterate them, find 
those,
who have this role, collect their principals and call in my realm method
clearCachedAuthorizationInfo(PrincipalCollection principals).
 
 
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Best regards, Alex Orlov