Software Design 2e - DIM

does review a number of structured methods although, again, we will not considerthem here.363Comparison frameworkAlthough not strictly a part of the comparison framework used in the study, Wieringaexpected a method to provide at least the following elements.nnnnTechniques for representing properties of software, such as diagrams.Interpretation rules for the techniques. Essentially this is the semantic element ofdiagrams, concerned with their meaning.Interconnection rules that describe how the different techniques inter-relate andcombine into a ‘coherent specification of software’.Heuristics for the use of the techniques.This model is quite similar to the viewpoint and process models used in this book,although it places more emphasis upon the structuring of the representation parts ofthe methods and less upon the processes (which may well be appropriate in an objectorientedcontext!).The framework used for the actual comparisons is not unlike that employed byIivari, although structured rather differently. This framework, and the rationale for itsuse, is discussed in some detail in the paper. In summary, the properties assessed foreach method consist of its ability to describe:Design processes for the object-oriented paradigmnnnnnnnsystem functions (what the system provides);system behaviour (how the system as a whole behaves over time);system communication (how the system interacts with external entities);conceptual decomposition (how the system is composed);component functions (what each component class provides);component behaviour (how component classes behave over time);component communication (how each class interacts with other classes).While also recognizing the need to model the non-functional properties of a designmodel, Wieringa observes that none of the methods reviewed in his survey offer techniquesfor doing so, and so omits this aspect from his comparison (as other authorshave also done).Key observationsOne of the problems inherent in conducting such a large-scale survey is how to emergewith anything coherent at the end. However, this survey does emerge with some interestingobservations and comments, largely because, as noted above, it looks quite