The humble beginnings...
In this article, we'll explore the SOLID Design Principles in object-oriented design. But before we delve into the exciting concepts, let's discuss the typical trajectory of a real-world software development cycle.
Typically, we commence with something straightforward, adhering to a given set of requirements. The goal is to rapidly build a solution, addressing all the intricacies. And there it is! The prototype succeeds, the demo wows the audience, leaving them thrilled and hungry for more. The team behind the success is jubilant, their enthusiasm soaring. They eagerly absorb feedback and embark on fulfilling new requirements.
And the golden mess...
This joyride continues for a while, but excitement wanes as the software evolves. The codebase, while a golden mess, somehow functions seamlessly. The realization dawns upon the team that accommodating that one more change would impact the existing codebase, tightly intertwined with its features.
The choice becomes clear: either handle the new case differently or redo a significant portion of the implemented work, now almost in a different method. Such scenarios arise when the codebase lacks generality & extensibility, and becomes a major challenge.
This exact issue was discussed by Robert C. Martin in his 2000 paper, "Design Principles and Design Patterns." Martin emphasizes that successful software evolves and becomes more complex over time. Without solid design principles, the code becomes rigid, fragile, hard to understand, and inextensible – a nightmare for developers. Fortunately, luminaries like Robert C. Martin and Michael Feathers introduced us to the SOLID design principles.
The formal introduction
So, what are the SOLID Principles? The answer is, these are popular set of design principles which are used in object-oriented programming based software development. SOLID is an acronym which stands for five key design principles. These are:
Single responsibility principle
Open-closed principle
Liskov substitution principle
Interface segregation principle
Dependency inversion principle
Over the last two decades, these principles have revolutionized object-oriented programming, offering a framework to avoid common design mistakes. While not silver bullets, they help minimize tight coupling, ensuring changes in one area don't impact others. These principles encourage developers to create designs that are easy to understand, reuse, maintain, and flexible enough to accommodate changes and future extensions. In essence, these design techniques help mitigate challenges that arise with each iteration of code evolution.
In the following threads, we'll delve into each of these principles, showcasing them in action with code snippets. Until then, adios!