Software Metrics Proposal for Conformity Checking of Class Diagram to SOLID Design Principles

Good software design quality is needed to reduce the number of errors in the implementation and testing phase. The SOLID design principles have been used as an object-oriented design guideline to meet software quality factors, such as understandability, flexibility, maintainability, and testability. In this paper we propose a set of metric to measure the conformity of class diagram to SOLID principles. In this study, we have analyzed the relationship between the concepts of SOLID principles with class diagram metrics, the metrics for each principles and the measurement techniques for class diagrams are produced. The proposed metrics for SRP, OCP, LSP, ISP, and DIP are respectively VSRP (Value of SRP), VOCP (Value of OCP), VLSP (Value of LSP), VISP (Value of ISP) and VDIP (Value of DIP). The metric has been validated using 15 class diagrams extracted from seven software applications. A spearman's rank correlation has been used and it has described the correlation between the metrics. This suggests that the proposed metrics have demonstrated their practicality.