Collapse Hierarchy

See http://www.refactoring.com/catalog/collapseHierarchy.html

This refactoring merges a superclass and subclass into a single class.

It is used when one of those classes provides little value. This condition occurs when a developer pre-emptively designs a deep class hierarchy or after other refactorings have moved most of the functionality out of one of the classes.

This refactoring uses the refactorings PullUpField?, PullUpMethod?, PushDownMethod?, PushDownField?.

See MaxThreeLayersOfInheritance

CategoryRefactoring