Metamodelling for Software Engineering

5.4 SUMMARY

In this chapter, we have discussed in detail two possible responses to the challenge of multi-layer integration of process and product modelling. The issue to be resolved is primarily the need in a methodology to standardize attributes in the metamodel but not to realize them as values until the enactment occurs. For most metamodelling hierarchies (as exemplified by Figures 2.19 and 2.20), this requires a two-stage process: the metamodel attribute definition must pass into an intermediate layer or domain unchanged (i.e. still definitional) and then be instantiated from a definition into a value when crossing into the lowest domain, that of the endeavour and the enactment of the method on a real project or projects.

Such deep instantiation may be addressed by the application of a concept called potency [2; 3; 14] or by powertypes [7; 10; 15]. Both these solutions have been explored in detail and then contrasted in Section 5.3. For the purposes of further discussion, in Chapters 6 and 7, of standardization and method construction, respectively, we adopt the powertype-based solution.