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.
