Generalization and Specialization - Notes by Shariq SP

Generalization and Specialization in Object-Oriented Programming

Generalization and Specialization are fundamental concepts in Object-Oriented Programming (OOP) that allow you to create hierarchical relationships between classes, enabling code reuse and abstraction. Let's delve deeper into these concepts:

Generalization

Generalization is the process of extracting common characteristics from two or more classes and combining them into a more general superclass. It involves identifying shared attributes and behaviors among classes and creating a higher-level abstraction that encapsulates these commonalities.

Rules for Generalization:

  • Identify common attributes and behaviors among classes.
  • Create a superclass that represents the common features.
  • Place the shared attributes and methods in the superclass.
  • Subclasses inherit the attributes and methods from the superclass.

Specialization

Specialization, also known as inheritance, is the opposite process of Generalization. It involves creating more specific subclasses from a general superclass by adding additional attributes or behaviors.

Rules for Specialization:

  • Create a subclass that extends the superclass.
  • Add unique attributes or behaviors specific to the subclass.
  • Override methods if necessary to customize behavior.
  • Subclasses inherit the attributes and methods from the superclass and can add their own.

Examples:

1. Animal Hierarchy:

  • Generalization: Abstract class 'Animal' with common attributes like 'name' and 'age' and methods like 'eat()' and 'sleep()'.
  • Specialization: Subclasses like 'Dog', 'Cat', and 'Bird' inheriting from 'Animal' and adding specific behaviors like 'bark()', 'meow()', and 'fly()' respectively.

2. Vehicle Classification:

  • Generalization: Abstract class 'Vehicle' with common attributes like 'model' and 'year' and methods like 'start()' and 'stop()'.
  • Specialization: Subclasses like 'Car', 'Motorcycle', and 'Truck' inheriting from 'Vehicle' and adding specific features like 'numberOfDoors', 'hasSideCar()', and 'cargoCapacity' respectively.

3. Employee Management System:

  • Generalization: Abstract class 'Employee' with common attributes like 'name' and 'id' and methods like 'calculateSalary()'.
  • Specialization: Subclasses like 'Manager', 'Developer', and 'HR' inheriting from 'Employee' and adding specific functionalities like 'approveLeave()', 'writeCode()', and 'conductInterview()' respectively.

Advantages:

  • Code Reusability: Generalization allows common code to be reused across multiple subclasses, reducing redundancy and promoting maintainability.
  • Abstraction: Generalization abstracts common features into a superclass, providing a high-level view of the system and hiding implementation details.
  • Flexibility: Specialization enables customization and extension of functionality in subclasses while preserving the core behavior defined in the superclass.
  • Scalability: Hierarchical class structures facilitate the addition of new subclasses without affecting existing code, making the system more scalable and adaptable to change.
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