Johnson and Foote's heuristics

See Designing Reusable Classes

Johnson and Foote 1988

• Recursion introduction
• Eliminate case analysis
• Reduce the number of arguments
• Reduce the size of methods
• Class hierarchies should be deep and narrow
• The top of the class hierarchy should be abstract
• Minimize accesses to variables
• Subclasses should be specializations
• Split large classes
• Factor implementation differences into subcomponents
• Separate methods that do not communicate
• Send messages to components instead of to self
• Reduce implicit parameter passing