Factor implementation differences into subcomponents

This is Rule 10 in Johnson and Foote 1988.

If different subclasses implement a method in one of a few ways, then the method may not be directly related to the superclass and the implementation should be separated by creating a class hierarchy and composing it within the superclass.

This means that multiple subclasses can contain the same implementation without repeated code.

See Also

• Strategy
• Johnson and Foote 1988
• Don't repeat yourself