Ontology for user management?

i want o create an ontology that would enable me to mange the users and grant specific rights to them based on their role.Suppose, i have a main node called Users, within the main node, i have sub-nodes like Administrator, Analyst,Normal User,Executive etc. to each of these sub-nodes, i want to grant specific rights  like Administrator can maintain records and publish them whereas a Normal User can only view the records and nothing else...on a similar fashion i would like to grant particular privileges.at the same time,tomorrow if i want to add a new type of user,i should be able to do that easily.
Kindly throw some light on this topic.i really need it . i would be really grateful if u could add code snippets as well...
anticipating an early response .
thank you!

Well it's hard to provide code snippets when we don't know whether you are creating access controls for a file system, for a database, for a web app, or....

My first suggestion would be not to reinvent the wheel if possible, i.e. use NTFS if you are controlling access to filesystem objects.

If you are using ASP .NET, you can take advantages of the Role Manger provider in ASP .NET 2.0.  You can extend the providers to support whatever access control logic you want.  For more info see:

http://msdn.microsoft.com/asp.net/beta2/providers/default.aspx

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnpag2/html/paght000019.asp

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnpag2/html/paght000018.asp

http://www.theserverside.net/articles/showarticle.tss?id=CreatingProfileProvider

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnpag2/html/paght000013.asp

Access controls can be really complicated -- multiple group memberships, conflicting sets of permissions, whether the permissions apply to nodes, the objects IN the nodes, inheritance, etc.  If you are rolling your own, It's definitely one of those things where you want to spend most of your time getting the DESIGN right. 

Good luck!

Thank you karim....i am looking into these possibilities...

but could u suggest me how to implement the same using J2EE framework...coz my existing code is in J2EE itself...it would be really gr8 if u cud provide some links for the same..

At a guess, you probably want to look as JAAS. Not sure a Microsoft site is necessarily the best place to get advice on Java security implementations though...

Thank you andy...i really appreciate ur concern...Actually, i was looking for something specific to ontology...where we create a main node..and sub-nodes within..so, if i have USERS as the main node, then i'll have types of users as the subnodes.To those types of users, i want to assign specific rights through my ontology framework itself(using OWL)..
could u throw some more light into the matter?
Thank You