Criteria and Guidelines to Improve Software Maintainability in Software Product Lines

Software Product Line (SPL) consists of an approach for supporting software design and development to promote large-scale and systematic reuse of components. Reuse in SPLs is enabled by using common features of a domain composing the SPL's core and other features defining variation points. Features can be defined as modules of an application with consistent, well-defined, independent, and combinable functions. Changes in SPLs can be more complex than in single systems because changes in a module can impact on more than one product. In this paper, the goal is to propose criteria for identifying possible problems and guidelines for increasing Maintainability Index (MI) of software generated by SPL. Seven criteria were created and guidelines were elaborated and associated to these criteria. The criteria were used to identify possible problems related to legibility and complexity of features' source code. The guidelines were used to solve or minimize problems identified. To verify the effectiveness of the criteria and guidelines, a case study was performed by applying the criteria and guidelines on TankWar SPL in two conditions: criteria and guidelines applied (i) separately and (ii) cumulatively by following a proposed sequence. After applying criteria and using guidelines, an improvement in the maintainability index of up to 17.65 points was achieved. The study showed that criteria and guidelines were effective to improve the maintainability of TankWar SPL.