Design Pattern Decay: An Extended Taxonomy and Empirical Study of Grime and its Impact on Design Pattern Evolution

Design patterns are well known solutions to common problems and are extensively utilized in software development. Yet, little empirical work has been conducted to evaluate or validate the consequences that poor design decisions have on pattern realizations. This paper describes a research program to further the understanding of design pattern evolution. Specifically, we focus on design pattern decay by studying how grime, a decisively negative consequence of software evolution occurs. The research proposed herein furthers the exploration of design pattern decay by providing empirical evidence of grime buildup, a new grime taxonomy, and the consequences exhibited through decreased adaptability and maintainability in actual realizations of patterns in code. These notions will be supported through the development of semi-automated grime detection and refactoring research tools that will also link to existing forms of design decay such as code smells, anti-patterns, and modularity violations. An extension of this research focuses on the exploration of these notions inlying coupled pattern realizations.