Open Closed Principle (OCP)

The Open-Closed Principle states that software entities (e.g., classes, modules, functions) should be open for extension but closed for modification. This means that the behavior of a module can be extended without altering its source code, helping maintain stability and avoid introducing bugs.

Key aspects of OCP

• Open for Extension: New functionality can be added without changing the existing code.
• Closed for Modification: The existing code should not require changes when extending functionality.
• Decoupling and Scalability: Promotes a modular design where changes in one part don’t ripple through the system, making it easier to scale and maintain.

Example

Imagine a shape-drawing program. Initially, it supports only circles, and you need to add functionality for rectangles:

• Instead of modifying the existing Shape class, you can extend it by adding new classes like Rectangle that implement the same interface.
• This ensures the original class remains unchanged, preserving its tested functionality while allowing new features.

By adhering to OCP, developers create systems that are more flexible, maintainable, and easier to enhance without compromising the integrity of the existing codebase.