A class, in any object-oriented language, can be thought of as a blueprint for creating objects—defining what those objects, as instances of the class, are, have, and can do. Classes frequently represent real world objects, be they people, places, or things, but even when they don't, they provide a concise set of data and capabilities/functionality that fits into a logical conceptual unit.
As hms_sys development progresses, there will be several classes, both concrete and abstract, that will be designed and implemented. In most cases, the design will start with a class diagram—a drawing of one-to-many classes that shows the structure of each and any relationship between them:
A Concrete Class is intended to be instantiated, to have object instances created from the blueprint it provides. An Abstract Class provides baseline functionality...