The Evolution of Role-Stereotypes and Related Design (Anti)Patterns

Abstract: This paper presents a study on how classes based on the role-stereotypes defined by Wirfs-Brock, change over time in software systems, and how the occurrence of anti-patterns change over time in relation to these roles. The aim of the study is to gain an understanding on how role-stereotypes change as softwaresystems evolve, and if these changes have possible correlations to certain anti-patterns. With an exploratory approach, we performed studies on the evolution of role-stereotypes and anti-patterns in three open source projects: Bitcoin Wallet, K9 Mail and Sweet Home 3D. By using descriptive graphs and through observation, we demonstrate how the distribution of role-stereotypes and the distribution of anti-patterns evolve over a selected number of versions of the three projects. Furthermore, we also analyzed the changes in role-stereotypes in relation to the the occurrence of anti-patterns in these roles. Additionally, we analyzed if there are certain roles that are more prone to switch to other roles. We found that some changes in the occurrence of anti-patterns seems to be reflective to the changes in the distribution of role-stereotypes, and that the occurrence of anti-patterns in specific role-stereotypes seems to have more in common with the occurrence of anti-patterns in different roles in the same project, rather than with the occurrence of anti-patterns in the same roles in different projects. We also found that certain role-stereotypes are more prone to change role to other certain roles. Therefore this study brings new insight to software developers and designers on the behaviour and nature of role-stereotypes and anti-patterns, when using classes designed based on rolestereotypes.