Safely creating correct subclasses without seeing superclass code

Abstract

A major problem for object-oriented frameworks and class libraries is how to provide enough information about an extensible superclass so that programmers can safely create new subclasses without studying superclass code. The goal of my work is to determine what information is needed so library providers do not have to give away the code of library superclasses. A closely related goal is to provide guidelines that simplify reasoning about classes that inherit from such frameworks and class libraries. The long-term goal of my research is to develop tool support to automatically generate some of the necessary documentation and to assist programmers in reasoning about how to create correct subclasses. © 2000 ACM.