Measuring, Assessing and Improving Software Quality based on Object-Oriented Design Principles

Good object-oriented design is crucial for a successful software product. Metric-based approaches and the identification of design smells are established concepts for identifying design flaws and deriving design improvements thereof. Nevertheless, metrics are difficult to use for improvements as they provide only weak guidance and are difficult to interpret. Thus, this paper proposes a novel design quality model (DQM) based on fundamental object-oriented design principles and best practices. In course of discussing DQM, the paper provides a contribution in three directions: (1) it shows how to measure design principles automatically, (2) then the measuring result is used to assess the degree of fulfilling object-oriented design principles, (3) and finally design improvements of identified design flaws in object-oriented software are derived. Additionally, the paper provides an overview of the research area by explaining terms used to describe designrelated aspects and by depicting the result of a survey on the importance of object-oriented design principles. The underlying concepts of the DQM are explained before it is applied on two open-source projects in the format of a case study. The qualitative discussion of its application shows the advantages of the automated design assessment that can be used for guiding design improvements.