OOP Design Guidelines

Question 1

What is OOP?

Answer 1

Object Oriented Programming.

It has a number of principles and guidelines to follow to get a good design.

Question 2

What are the OOP guidelines regarding Data Access?

Answer 2

Encapsulate objects and use getters and setters.
Classes should not expose how they work internally.
Minimize the accessibility of classes (private).

Question 3

How do you enforce encapsulation?

Answer 3

Set classes to private but use public getters and setters

Question 4

What is the DRY principle?

Answer 4

Don’t repeat yourself.

Basically if you are writing duplicate code you might want to create a class with the methods and extend them.

Question 5

What is the Principle of least knowledge (Law of Demeter)?

Answer 5

Classes should only collaborate with other classes where it is necessary. To keep the dependencies to a minimum which causes the class to be flexible.

Question 6

What is Inheritance?

Answer 6

It’s when a class inherits from a parent class. an “is a” relationship.

Question 7

Why does inheritance break the encapsulation rules?

Answer 7

because it opens up a class to another.

Question 8

What is the Single responsibility principle (class?

Answer 8

a class should only do one thing and do it well rather than having focus on many things.