Is A and Has A Concepts in Object-Oriented Design

Develpreneur: Become a Better Developer and Entrepreneur · Mar 12, 2021 · 15m

The ideas of "is a" and "has a" are often discussed as part of object-oriented design. These concepts may seem simple and obvious. However, they can often be confused, and complex systems can blur the lines between them. We start a multi-part episode going over these concepts focused on how "is a" relationships work.

Is A and Has A Defined

These concepts boil down to simple grammar. For two objects, A and B, here are the options.

A is a B if A has all of the traits of B. For example, a poodle is a dog because a poodle has the traits we equate to a dog. A dog is not a poodle, as some dogs have…