Applying Object Orientation to System Architecture

Abstract

In this chapter, we provide the essential theory and practical details of employing the principles of Object Orientation (OO) in system architecture modeling. We do not attempt to provide an exhaustive OO tutorial, since there exists a very large literature on this subject (see the references to this chapter). Our goal, instead, is to give the reader the level of understanding needed to master the MBSAP methodology and apply it to practical system architecting challenges. First, we present the rationale for OO and define the essential concepts and terminology, stressing the benefits it delivers in dealing with complex entities. Although we use the Systems Modeling Language (SysML) as the basis for this book, we begin by discussing and illustrating the primary diagrams of the Unified Modeling Language (UML), which is the root language standard for OO. This is then followed by a description of the changes to UML introduced by the SysML, which is defined as a Profile of UML. The reality is that a large part of the SysML is taken directly from the UML language specification. We believe understanding of this material is enhanced by first considering the parent UML and then explicitly showing how UML modifies and extends the language. We include generic UML and SysML diagrams that illustrate important principles and syntax and that can serve as format samples in developing real architecture models. Appendices A and B are concise references to UML and SysML, respectively, intended to give readers a quick and easy way to look up the details. Chapter objective: the reader will be able to create and read UML and SysML diagrams and to describe the role of each.