Patent ID: 8392961
Filing Date: 2013-03-05
Classification: G06F,H04L

Abstract:
1. A method of providing access control in a content-based publish/subscribe system, wherein messages are delivered from publishing clients to subscribing clients via a plurality of brokers, the method comprising the steps of: specifying one or more changes to an access control policy, wherein an access control policy specifies rights of clients to publish messages and to subscribe to and receive messages in the content-based publish/subscribe system; associating an access control version identifier to the one or more changes, wherein control version identifier comprises a numerical counter; sending the one or more changes to one or more brokers of the plurality of brokers that have a publishing client or a subscribing client associated therewith that is affected by the one or more changes; and sending the access control version identifier associated with the one or more changes to each of the plurality of brokers, wherein the plurality of brokers host one or more message streams, each of the one or more message streams comprising a series of messages published by one or more of the publishing clients; and wherein a given broker, upon receipt of the one or more changes, uses the access control version identifier to determine a starting point in a message stream hosted by the given broker such that (i) a message before the starting point in the message stream is delivered to a subscribing client when the message satisfies subscription and access rights before the change associated with the access control version identifier and (ii) a message after the starting point in the message stream is delivered to the subscribing client when the message satisfies the subscription and access rights after the change associated with the access control version identifier, wherein one or more of the steps of specifying, associating, and sending are implemented by a computer.