An Empirical Study on Design Pattern Usage on Open-Source Software

Currently, open source software communities are thriving and the number of projects that are available through well known code repositories is rapidly increasing over the years. The amount of code that is freely available to developers facilitates high reuse opportunities. One of the major concerns of developers when reusing code is the quality of the code that is going to be reused. Design patterns are well known solutions that are reported to produce substantial benefits with respect to software quality. In this paper, we investigate the extent to which design patterns are employed in open source software. More specifically, this study reports empirical results based on the number and type of design patterns retrieved from open source software projects. Up to now, one hundred and eight (108) open source software projects of various characteristics have been considered. The results of the study suggest that several patterns are more frequently used in open source software than others, that some patterns are more applicable in some categories than others and that program size, number of downloads, days of project activity and the number of developers are crucial factors that influence the use of design patterns in open source software project.