Composite design pattern

The Composite design pattern favors composition (commonly defined as a has a relationship) over inheritance (an is a relationship). The composition over inheritance approach has been a source of discussions among engineers since the nineties. We will learn how to create object structures by using a has a approach. All in all, Go doesn't have inheritance because it doesn't need it!

Description

In the Composite design pattern, you will create hierarchies and trees of objects. Objects have different objects with their own fields and methods inside them. This approach is very powerful and solves many problems of inheritance and multiple inheritances. For example, a typical inheritance problem is when you have an entity that inherits from two completely different classes, which have absolutely no relationship between them. Imagine an athlete who trains, and who is a swimmer who swims:

• The Athlete class has a Train() method
• The Swimmer class...