Reviewing Domain Structures and Components

Learn about detailed domain architectures, including aggregates, entities, events, and event handlers, for various domains within the application.

In The Sample Application chapter, 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 have some knowledge of how the consumer-producer pattern works and how the message broker facilitates that pattern, let’s explore each domain at length to review the pertinent objects within them.


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 doesn’t serve much of a purpose. The following illustration shows the domain architecture for the equipment domain:

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