Introduction

Cross-cutting concerns are unavoidable and create difficulties in the development and maintenance of large-scale systems. In this paper, we present a novel approach that identifies certain groups of code units that potentially share some cross-cutting concerns and recommends them for creating and updating aspects. Those code units, called concern peers, are detected based on their similar interactions (similar calling relations in similar contexts, either internally or externally). The recommendation is applicable to both the aspectization of non-aspect-oriented programs (i.e. for aspect creation), and the evolution of aspect-oriented programs (i.e. for aspect updating). The empirical evaluation on several real-world software systems shows that our tool XScan is scalable and provides useful recommendations.