1. A method for dynamically managing access to a resource in a computer system, the system having a client thereof making an access request for the resource, the method comprising: determining, via an application programming interface, based upon dynamic data and first dynamic policy whether a client authorization context is to be updated, wherein said first dynamic policy is tailored to an application through which the resource is accessed; identifying an access control entry as a callback access control entry; and in response to identifying the access control entry as a callback access control entry, evaluating, via said application programming interface, based upon dynamic data and second dynamic policy whether said callback access control entry bears on said access request, wherein said second dynamic policy is tailored to said application.