The following diagram shows a high-level view of event processing in the context of a modern architecture:
Figure 11
On the left-hand side, we can see the different systems acting as event producers. The following interactions can take place when an event is generated by one of the event producer systems:
The event is pushed into the event cloud.
Events are made available through the so-called enterprise event bus. In contrast to the enterprise service bus, the enterprise event bus only transports events. The ESB also handles service calls on an SOA system.
Events can be consumed directly by a consumer system on the right-hand side.
But, in most cases, events are handled by the event-processing component, which supports Event Stream Processing or Complex Event Processing.
The state and event store provide additional information to event processing—either historical events or reference data to support detecting derived events.
The Decide phase...