Free SOLID and design smells lessonsSOLID and design smells · Stage 1 · Substitution and dependencies · Step 1
Liskov substitution
What it takes for a subclass to be safely used wherever its parent is expected, and the behavioural rules beyond the type signature. About 13 minutes.
A subclass overrides a method to throw UnsupportedOperationException. What does that usually indicate?
- AA Liskov violation: the inheritance does not model a true is-a
- BA sound way to restrict a subclass
- CA performance optimisation
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A Liskov violation: the inheritance does not model a true is-a. Callers of the parent expect the operation to work.
4 questions on this idea
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