Reviewing domain structures and components
In Chapter 1, The Sample Application, we took a quick look at the outlined domains for the application, as well as a few (but not all) of the commands, events, entities, and other domain objects. Now that we are armed with some knowledge of how the consumer-producer pattern works and how the message broker facilitates that pattern, we will dive into each domain at length to review the pertinent objects within them.
Equipment
The equipment domain is of critical importance. Without a means to manage events that are related to the turnstile units, as well as the cameras in each unit, the application itself does not serve much of a purpose. The following diagram shows the domain architecture for the equipment domain:
The equipment domain is central to the application. Many events are triggered by events that originate from this domain.