Event-Driven Architecture (EDA)

There's a (relatively) new buzzword (buzzphrase?) gaining popularity, Event-Driven Architecture (EDA).

EDA is a technique for integrating applications where an emitter posts an announcement of an event and handlers receive notification of it. The announcements are transmitted as event messages. Often the event messages are transmitted using one or more publish/subscribe channels--where handlers register interest by subscribing to a topic, and emitters announce an event by publishing to the topic--but that's not a requirement. A topic can have multiple event handlers subscribed, but could have none at all. Once a handler receives notification, it reacts accordingly, perhaps by doing nothing. An event processing network is a more sophisticated connection between emitters and handlers, which performs mediation for event messages.

What are some examples of how to use an EDA?

An obvious question is: How does EDA relate to SOA and ESBs?

I also discuss EDA in developerWorks Interview with Bobby Woolf.

EDA enables complex event processing (CEP).

For more info:

• Event Driven Architecture (Wikipedia)
• "Event-driven architecture poised for wide adoption" (Computerworld)
• "Primer: Event-Driven Architecture" (eWeek)
• "Combining Service-Oriented Architecture and Event-Driven Architecture using an Enterprise Service Bus" (Jean-Louis Maréchaux of IBM)
• "TechEd 2005 Europe: Event-Driven Architectures" (Gregor Hohpe)
  • "Programming Without a Call Stack - Event-driven Architectures" (Gregor Hohpe)
• "The Growing Role of Events in Enterprise Applications" (Roy W. Schulte of Gartner)
• "Event-Driven Applications: Where they Apply and How they are Built" (K. Mani Chandy)

IBM Systems Journal has published an issue on EDA: Real-Time and Event-Based Systems.