Towards An Object-0riented Metric Modelling Process

Jon Avotins Department of Software Development Monash University, Caul eld Campus PO Box 197, Caul eld East Australia 3145 Email: [email protected] Abstract Two of the principal lessons to emerge from software measurement over the last twenty years have been the need for an e ective approach to metric modelling (Shepperd and Ince 1993), and the need for automated support of such a modelling approach (Fenton 1992). There are currently no tools which fully support an e ective metric modelling approach. This is in many respects responsible for the lack of success in the metrics eld, as measurement programs are usually driven by the tools available (Basili and Rombach 1988). We review existing system lifecycle models and metric modelling approaches to elucidate inherent problems of existing metric modelling approaches. We argue that there are various fundamental problems with existing metric modelling approaches, and that a subset of these mirror problems of earlier system lifecycle models. A list of criteria which a higher quality metric modelling approach should support are presented. Underlying concepts of recent object-oriented system lifecycle models and object-oriented software construction principles provide the appropriate technology to produce an object-oriented process for metric modelling (metric modelling approach and supporting software, which implicitly satis es the de ciencies of existing metric modelling approaches. 1 The Notion of Model A model can be informally de ned as \an abstraction or simpli cation of reality"(Shepperd and Ince 1993). A model requires a purpose, will establish relationships between entities, and has inputs and outputs, connected by relationships, or by a set of equalities which may use parameters, as illustrated in Figure 1. OUTPUTS MODEL PARAMETERS