UNIVERSITY OF HELSINKI Code and Design Metrics for Object-Oriented Systems

Object-oriented design and development has become popular in today’s software development environment. The benefits of object-oriented software development are now widely recognized. Object-oriented development requires not only different approaches to design and implementation; it also requires different approaches to software metrics. The metrics for object-oriented systems are different due to the different approach in program paradigm and in object-oriented language itself. An object-oriented program paradigm uses localization, encapsulation, information hiding, inheritance, object abstraction and polymorphism, and has different program structure than in procedural languages. There are quite a few sets of proposed metrics of object-oriented metrics for object-oriented software in the literature and research papers. The definition of six different metrics is presented in this document. The presented metrics are also validated by couple of real projects that use object-oriented language in their projects. Metric data provides quick feedback for software designers and managers. Analyzing and collecting the data can predict design quality. If appropriately used, it can lead to a significant reduction in costs of the overall implementation and improvements in quality of the final product. The improved quality, in turn reduces future maintenance efforts. Using early quality indicators based on objective empirical evidence is therefore a realistic target. It is unlikely that universally valid object-oriented quality measures and models could be devised, so that they would suit for all languages in all development environments and for different kind of application domains. It should be also kept in mind that metrics are only guidelines and not rules. They are guidelines that give an indication of the progress that a project has made and the quality of the design