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Event processing has emerged as one of the most important issues in IT today. It encompasses two separate ideas:

1. Event-driven Architecture (EDA), is a style of application architecture centered on asynchronous "push"-based communication. EDA is the architecture of choice for implementing "straight-through" multistage business processes that deliver goods, services and information with minimum delay. Processes designed using EDA are also easier to modify than traditional applications.

2. Complex-Event Processing (CEP), a sophisticated form of EDA, is used to extract the information value from multiple events. CEP systems find patterns in event data to detect opportunities and threats. Timely alerts are then pushed to the appropriate recipients, often using Business Activity Monitoring (BAM) dashboards. The result is faster and better operational decisions and more timely responses.

Gartner has organized a new conference on event processing and BAM to be held from September 19 - 21, 2007 in Orlando, Florida to address both aspects of event processing. See http://www.gartner.com/it/page.jsp?id=502259&tab=overview for more information. This article is an introduction to EDA to provide background for those who will attend the conference or for anyone who wants to learn more about the subject. CEP is covered in a related article, "Understanding the Role of Event Processing in Modern Business."

Sense and Respond

We live in an event-driven world. Animals, people and companies survive and thrive based on their ability to act quickly on opportunities and threats. Zebras on the savannah sense and respond to the opportunity of a water hole or the threat of a lion. Wall Street traders use algorithmic trading systems that act on arbitrage opportunities in sub-second response times. Banks track credit card usage to stop fraudulent charges as they occur.

Opportunities and threats appear at unpredictable times so an event-driven entity responds at times that are externally determined. Event-driven applications are initiated when a shipping company delivers goods, a customer submits a change of address or the price of a stock goes up. These happenings are business events: meaningful changes in the state of something relevant to the business. An event object is a report that documents the event. For example, the fact that Fred withdrew $ 100 from his bank account at 10 AM today is an event. The computer record associated the withdrawal transaction, perhaps in the form of an XML message, is the event object.