Interface Segregation Principle (ISP) Explained in Seconds

? Interface Segregation Principle (ISP) Explained Simply

The ISP, a core component of the SOLID design principles, states: Clients shouldn't be forced to depend on methods they don't use.

Overly broad interfaces, packed with unrelated methods, lead to classes burdened with unnecessary code. This results in brittle, difficult-to-maintain systems. ISP advocates for smaller, more focused interfaces for cleaner, more manageable code.

? A Simple Analogy

Imagine a restaurant menu overflowing with dishes you dislike. Navigating this unwieldy menu is frustrating! Now picture specialized menus: one for sandwiches, another for sushi, a third for desserts. Ordering becomes significantly easier. This illustrates the essence of ISP:

? Avoid massive, generic interfaces with unused methods.

✅ Embrace small, targeted interfaces tailored to specific client needs.

Code Examples

? Key Advantages

✅ Eliminates unnecessary methods: Classes only implement the methods they require.

✅ Improves code readability, maintainability, and extensibility.

✅ Promotes cleaner design: No more unused or unsupported methods.

⚠️ Recognizing ISP Violations

❌ Overly large interfaces. ❌ Unimplemented methods in classes.

? Avoiding ISP Violations

✅ Refactor large interfaces into smaller, more specialized ones. ✅ Implement only necessary methods—classes should only handle relevant functionality. ✅ Prioritize composition over inheritance for greater flexibility and extensibility without compromising ISP.

? Explore More

Want to learn more? Explore other posts in my programming principles series!

• Liskov Substitution Principle (LSP) Explained in 100 Seconds
• KISS Design Principle Explained in 100 Seconds
• DRY Principle Explained in 100 Seconds
• "Tell, Don't Ask" Principle Explained in 100 Seconds
• Golang Dependency Injection - Just in 5 Minutes!

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