Assessing the impact of aspects on model composition effort

Model composition is a common operation used in many software development activities---for example, reconciling models developed in parallel by different development teams, or merging models of new features with existing model artifacts. Unfortunately, both commercial and academic model composition tools suffer from the composition conflict problem. That is, models to-be-composed may conflict with each other and these conflicts must be resolved. In practice, detecting and resolving conflicts is a highly-intensive manual activity. In this paper, we investigate whether aspect-orientation reduces conflict resolution effort as improved modularization may better localize conflicts. The main goal of the paper is to conduct an exploratory study to analyze the impact of aspects on conflict resolution. In particular, model compositions are used to express the evolution of architectural models along six releases of a software product line. Well-known composition algorithms, such as override, merge and union, are applied and compared on both AO and non-AO models in terms of their conflict rate and effort to solve the identified conflicts. Our findings identify specific scenarios where aspect-orientation properties, such as obliviousness and quantification, result in a lower (or higher) composition effort.