Network Motifs in Object-Oriented Software Systems

TL;DR

This paper explores the structural patterns in object-oriented software systems using complex network theories, revealing that stable motifs are more abundant and tend to be functionally cloned, aiding software evolution analysis.

Contribution

It introduces the application of complex network motifs to analyze software evolution, highlighting the relationship between motif stability, abundance, and structural duplication.

Findings

Stable motifs are positively correlated with their abundance.

High Z score motifs tend to have stable structures.

Software evolution involves functional cloning and structural duplication.

Abstract

Nowadays, software has become a complex piece of work that may be beyond our control. Understanding how software evolves over time plays an important role in controlling software development processes. Recently, a few researchers found the quantitative evidence of structural duplication in software systems or web applications, which is similar to the evolutionary trend found in biological systems. To investigate the principles or rules of software evolution, we introduce the relevant theories and methods of complex networks into structural evolution and change of software systems. According to the results of our experiment on network motifs, we find that the stability of a motif shows positive correlation with its abundance and a motif with high Z score tends to have stable structure. These findings imply that the evolution of software systems is based on functional cloning as well as structural duplication and tends to be structurally stable. So, the work presented in this paper will be useful for the analysis of structural changes of software systems in reverse engineering.