You are designing a plugin system where plugins have widely varying capabilities. Some plugins implement only a few features, others implement many. Which design approach best aligns with SOLID principles, especially ISP and DIP, to maximize flexibility and maintainability?
AAvoid interfaces and use reflection to invoke plugin methods dynamically.
BDefine multiple small interfaces representing distinct capabilities and let plugins implement only those they support, injecting dependencies via abstractions.
CUse concrete base classes with default implementations for all features and let plugins override as needed, avoiding interfaces.
DCreate one large interface with all possible plugin methods and require all plugins to implement it, using runtime checks for unsupported features.
Step-by-Step Solution
Solution:
Step 1: Understand plugin variability
Plugins vary widely in supported features.
Step 2: Apply ISP and DIP
Defining multiple small interfaces representing distinct capabilities and letting plugins implement only those they support, injecting dependencies via abstractions, aligns with ISP and DIP.
Step 3: Evaluate other options
Creating one large interface forces fat interfaces violating ISP. Using concrete base classes reduces flexibility and violates DIP. Avoiding interfaces and using reflection bypasses type safety and is error-prone.
Final Answer:
Option B -> Option B
Quick Check:
Small interfaces + DI -> flexible, maintainable plugin design [OK]
Quick Trick:Small interfaces + DI maximize plugin flexibility [OK]
Common Mistakes:
MISTAKES
Forcing all plugins to implement large interfaces
Using concrete base classes instead of abstractions
Relying on reflection over interfaces
Trap Explanation:
PITFALL
Candidates often choose fat interfaces or concrete classes for convenience, ignoring SOLID benefits.
Interviewer Note:
CONTEXT
Tests real-world application of ISP and DIP in extensible systems.
