Objects and roles: modeling based on the dualistic view

T Tamai
1999 Information and Software Technology  
Software engineering has been producing a number of models or modeling methods, e.g. the data flow model, the state transition model, and the entity relationship model, just to name a few [35] . Models are in general composed of elements and structures combining those elements. Thus, the problem of constructing a "good" model depends on how to choose an appropriate set of model elements and how to identify a meaningful structure composed of those elements. Models are developed mainly for two
more » ... ectives. One is to map a real world or domain to a model so as to enable analysis on the problem within its context. Domain models and analysis models fall in this category. The other objective is to build a system image to be developed as a model. System models and design models are examples of the latter. Elements of system design models have traditionally been called modules and the process of identifying modules is called modularization. Ever since object-oriented technology was widely recognized as applicable not only to programming but also to analysis and design, objects have been adopted as the elements of models. Now, object models are being used "seamlessly" from the analysis phase through the design phase and to the implementation phase. When modeling process, regarded as an activity of identifying objects and their structures, is conducted in the top-down manner, it can be called decomposition and when conducted in the bottom-up manner, it can be called composition. Although the terms composition and decomposition have been used for a long time in conventional modularization techniques, they are still valid in the context of object-orientation. Actual modeling is not a pure composition or decomposition process but some mixture of the two. But still it should be correct to say that the major task of modeling is achieved by way of composition and decomposition. However, there have been arguments that the monistic view of modeling based solely on objects is often insufficient. Instead, a dualistic view based on objects and roles are advocated by a number of researchers and practitioners. Motivations for introducing roles are various and relations put between objects and roles are also different
doi:10.1016/s0950-5849(99)00075-0 fatcat:izgeghjpsrgq7hijqi2zhenda4