Which guideline is violated when an API allows subclassing for concrete classes without documentation?

Which guideline is violated when an API allows subclassing for concrete classes without documentation?

• A. G21 Don't force exceptions for control flow
• B. G24 Overload with care
• C. G13 Design/document for inheritance or prohibit it
• D. G9 Avoid overly clever APIs

Answer: (C)

When an API allows subclassing for concrete classes without appropriate documentation, it violates the guideline that advises designing and documenting for inheritance or prohibiting it entirely. This guideline emphasizes the importance of clarity and transparency when designing APIs that involve inheritance. Concrete classes are typically not intended to be subclassed since they can lead to unforeseen complexities and bugs if not properly managed. When this guideline is violated, developers who interact with the API may not have a clear understanding of how to appropriately extend the functionality of the concrete classes. They could unknowingly create subclasses that behave unpredictably or introduce issues that are difficult to debug, undermining the effectiveness and reliability of the API. Proper documentation is crucial in guiding users on how to use inheritance correctly, helping them avoid pitfalls associated with subclassing. This focus on careful design and documentation ensures that the API remains robust and maintainable, allowing developers to make informed decisions when extending the functionality provided by the API.

When an API allows subclassing for concrete classes without appropriate documentation, it violates the guideline that advises designing and documenting for inheritance or prohibiting it entirely. This guideline emphasizes the importance of clarity and transparency when designing APIs that involve inheritance. Concrete classes are typically not intended to be subclassed since they can lead to unforeseen complexities and bugs if not properly managed.

When this guideline is violated, developers who interact with the API may not have a clear understanding of how to appropriately extend the functionality of the concrete classes. They could unknowingly create subclasses that behave unpredictably or introduce issues that are difficult to debug, undermining the effectiveness and reliability of the API. Proper documentation is crucial in guiding users on how to use inheritance correctly, helping them avoid pitfalls associated with subclassing.

This focus on careful design and documentation ensures that the API remains robust and maintainable, allowing developers to make informed decisions when extending the functionality provided by the API.