Java Datastore Design approach User,Roles,Groups,Permission

[ANKIT BHARTI]

Hi

I wanted to know how we can model datastore to manage Role-Based Access Controls mechanism in App Engine unlike traditional RDMS ?

• A user can have multiple roles.
• A role can have multiple users.
• A role can have 1 or more permissions.
• A permission can be assigned to many roles.
• An operation can be assigned many permissions.
• A permission can be assigned to many operations.

Also if someone can suggest the best possible UI components to manage the above layout.