Functional Kotlin

Inheritance

As we continue modelling our domain in Kotlin, we realize that specific objects are quite similar. If we go back to our HR example, an employee and a contractor are quite similar; both have a name, a date of birth, and so on; they also have some differences. For example, a contractor has a daily rate, while an employee has a monthly salary. It is obvious that they are similar—both of them are people; people is a superset where both contractor and employee belong. As such, both have their own specific features that make them different enough to be classified into different subsets.

This is what inheritance is all about, there are groups and subgroups and there are relationships between them. In an inheritance hierarchy, if you ...