Composite Subscriptions in Content-Based Publish/Subscribe Systems

We use distributed publish/subscribe systems to process events in distributed systems. However,There is no algorithms that support for expressing patterns about distributed events. Inspired from the requirements of decentralized, event-driven workflow processing, They have designed a subscription language for expressing correlations among distributed eventsand they illustrate the approach with a workflow management case study. The language is validated and implemented in PADRES. In [LJ], they present PADRES, including its novel features which are the composite subscription language, the coordination patterns, the composite event detection algorithms, the rule-based router design, and a case study. The experiments show that rule-based brokers are a viable and powerful alternative to existing, special-purpose, content-based routing algorithms. The experiments also show that the use of composite subscriptions in PADRES will reduce the network bandwith usage.