More on inheritance

Inheritance is something that comes up quite often during my programming experience. Whenever I have classes that share some logic or properties, I think of inheritance. However, sometimes, using inheritance ends up making a design more brittle. Through my experience and reading, I have learned a few things about inheritance.

Notes on the Interface Segregation Pattern

The Interface Segregation Pattern (ISP) is one of the principle in SOLID. As a recap, SOLID is an acronym which stands for the five software design principles:

• The Single Responsibility Principle
• The Open Closed Principle
• The Liskov Substitution Principle
• The Interface Segregation Principle
• The Dependency Inversion Principle

Notes on Barbara Liskov paper on data abstraction and hierarchy

In October 1987, Barbara Liskov published a research paper in which she discussed about different but related concepts: data abstraction, inheritance, encapsulation, implementation hierarch, type hierarchy and polymorphism. I’ve found the paper to be insightful and informative. In this post, I simply give a recap of what I have learned and share my thoughts from reading the paper.

The Liskov Substitution Principle

In the previous post, I wrote about Barbara Liskov research paper on data abstraction and hierarchy. In the paper, the author states a property which exists between type and subtype. That property later becomes known as the Liskov Substitution Principle. In this post, I continue to go over the principle in more details and give examples. The principle is one out of the five software design principles in SOLID:

• S: Single Responsibility Principle
• O: Open Closed Principle
• L: Liskov Substitution Principle
• I: Interface Segregation Principle
• D: Dependency Inversion Principle