Introduction to OOP Chapter 17: The Polymorphic Variable : next previous audio real text

The Receiver Variable in Frameworks

The greatest power of the receiver variable comes in the development of software frameworks.

In a framework, some methods are implemented in the parent class and not overridden (called foundation method), others are defined in the parent class, but intended to be overridden (called deferred method).

Consider a class Window with subclasses TextWindow and GraphicsWindow.

The combination of foundation and deferred methods allow high level algorithms to be reused and specialized in new situations.

Intro OOP, Chapter 17, Slide 04