Improving Code Maintainability: A Case Study on the Impact of Refactoring

It is a fact that a lot of software is written by people without a formal education in software engineering. As an example, material scientists often capture their knowledge in the form of simulation software that contains sophisticated algorithms representing complex physical concepts. Since software engineering is typically not a core skill of these scientists, there is a risk that their software becomes unmaintainable once it reaches a substantial size or structural complexity. This paper reports on a case study in which software engineers consulted magnetics researchers in refactoring their simulation software. This software had grown to 30 kloc of Java and was considered unmaintainable by the stakeholders of the research project. The case study describes the process of refactoring a system under the guidance of a software engineer with results supported by static analysis and software metrics. It shows how software engineers evaluated and selected refactorings to apply to the system using their expert judgment with input from static analysis tools and discusses the outcome of refactoring as evaluated by code owners and reported via static analysis metrics.