A Method to Investigate Software Evolutions Using Design Pattern Detection Tool

In software designing, design patterns are expected to help for implementing with clear design intention with higher quality. However, selecting appropriate patterns is not simple task, and design patterns are sometimes de-ployed exploratory without properly defined process. In or-der to clarify design patterns ’ contribution to the quality and productivity, it is very important to investigate design pattern usage among the series of revisions over the time. In this paper, we propose a method to observe design pattern usage in the series of source code modifications by using a design pattern detection tool and source code man-agement system. This method enables intuitive analysis of design pattern history that should have strong relations to the software evolutions, without any preserved design docu-ments. We also present an analysis to revisions history of an open source software JUnit, as a preliminary experimenta-tion of our method. In this analysis, number of design pat-terns in the source code are observed, and we found some patterns of significant increase/decrease of these numbers are useful to determine the type of each modification such as feature enhancement or refactoring. 1