Inheritance and Refinement in Object-Oriented Programming

Study Notes

Object-Oriented (OO) Design

A class defines the general properties and behaviors for a set of objects.
An instance of a class is an object with the class's type.
Top classes that the application will use are defined at high-level design.
Identify main classes by looking for nouns in a description of the application's features.

Hierarchy and Inheritance

Inheritance supports hierarchical classification and provides code reuse.
A child class is derived from the parent class, inheriting properties, methods, and events.
Example: Yaris and Jazz are child classes of Car, inheriting properties, methods, and events.
Refinement is the process of breaking a parent class into multiple subclasses to capture differences between objects.

Refinement

Refinement focuses on behavioral differences between classes.
Refined classes include properties, methods, and events.
Example: Automatic and Manual classes inherit Acceleration property from Car class.

Generalization

Generalization extracts common features from two or more classes to define a parent class.
Example: ClassyDraw Application has classes such as Rectangle, Ellipse, Polygon, Text, Line, Star, and Hypotrochoid.

Low-Level Design

Low-level design focuses on "how" and defines refined classes including properties, methods, and events.
Properties define the information the class needs, methods define the actions the class needs to perform, and events define notifications.

Building Inheritance Hierarchies

Inheritance is a mechanism by which an object acquires properties, methods, and events of another object.
Generalization creates a parent class, and inheritance builds a hierarchy of subclasses.

Composition

Composition provides code reuse and allows including multiple copies of a type of object inside a class.
Example: Company class includes a Person object with FirstName, LastName, Address, and PhoneNumber properties.

Database

A database is a collection of related information that is organized for easy access, management, and update.
Database design is the process of producing a detailed data model of a database.
Relational databases are simple and easy to use, providing tools for searching, combining data, and sorting results.

Description

Explore the concepts of inheritance and refinement in object-oriented programming. Learn how child classes derive properties, methods, and events from a parent class. Understand the process of refinement by breaking a parent class into multiple subclasses to capture differences between objects.