Abstract

We introduce a simple, programming language independent rule (known in-house as the Law of Demeter) which encodes the ideas of encapsulation and modularity in an easy to follow form for the object-oriented programmer. The rule achieves the following related benefits if code duplication, the number of method arguments and the number of methods per class are minimized: Easier software maintenance, less coupling between your methods, better information hiding, methods which are easier to reuse, and easier correctness proofs using structural induction. We show relationships between the Law and software engineering techniques, such as coupling control, information hiding, information restriction, localization of information, narrow interfaces and structural induction. We discuss two important interpretations of the Law (strong and weak) and we prove that any object-oriented program can be transformed to satisfy the Law. We express the Law in several languages which support object-oriented p...

Citations