Object Oriented Design Pattern Inference

Abstract

When designing a new application, experienced software engineers usually try to employ solutions that proved successful in previous projects. Such reuse of code organizations is seldom made explicit. Nevertheless it represents important information about the system, that can be extremely valuable in the maintenance phase, by documenting the design choices underlying the implementation. In addition, having it available, it can be reused whenever a similar problem is encountered.

In this paper an approach is proposed to the inference of recurrent design patterns directly from the code or the design. No assumption is made on the availability of any pattern library, and the concept analysis algorithm, adapted for this purpose, is able to infer the presence of class groups which instantiate a common, repeated pattern. In fact, concept analysis provides sets of objects sharing attributes, which, in the case of object oriented design patterns, become class members or inter-class relations.

The approach was applied to a C++ application, for which the structural relations among classes led to the extraction of a set of structural design patterns, which could be enriched with non structural information about class members and method invocations. The resulting patterns could be interpreted as meaningful organizations aimed at solving general problems which have several instances in the analyzed application.

Postscript version of the paper.