An autonomic messaging middleware with stateful stream transformation

We report on the design and prototype implementation of the SMILE system. SMILE (Smart Middleware Light Ends) extends the Gryphon publish-subscribe system with stateful subscriptions and computing capabilities, with the goal of raising the abstraction level of messaging middleware programming closer to that of database programming. It allows subscriptions to relational views (which can involve aggregation, joins, and other transforms) derived from published event streams. The SMILE system has dual autonomic properties: it can be used to augment other system with monitoring capabilities and make them more autonomic; and the system itself has sophisticated capabilities for self-optimization, deployment and automated fault-tolerance.