Enterprise service bus in a nutshell

Event processing consists of taking one or more events from an event stream and applying actions over those events. In general, in an enterprise service bus, there are commodity services; the most common are the following:

• Data transformation
• Event handling
• Protocol conversion
• Data mapping

Message processing in the majority of cases involves the following:

• Message structure validation against a message schema
• Given an event stream, filtering the messages from the stream
• Message enrichment with additional data
• Message aggregation (composition) from two or more message to produce a new message

This chapter is about event validation. The chapters that follow are about composition and enrichment.