Chapter 9. Inheritance

The relationship between a class and its subclass often starts being simple but gets more complicated over time. A subclass will often depend on its parent more intimately than will a separate class, but it can go too far.

A key challenge is deciding what a class is versus what a class has. A class structure often starts with inheritance and moves to a more compositional style over time.

Smells Covered

  • Refused Bequest

  • Inappropriate Intimacy (Subclass Form)

  • Lazy Class

See also these other smells related to inheritance:

Refused Bequest

Symptoms

  • A class inherits from a parent, but throws an exception instead ...

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