MY BOOK REVIEW

OBJECT ORIENTED ANALYSIS and DESIGN

Book

Edward Yourdon and Carl Argila

Author

QA 76.64 Y68 1996

Reference no.

CHAPTER 5

“The whole of science is nothing more than a refinement of everyday thinking”.

• Albert Einstein

Object Oriented Development (OOD) has been touted as the next great advance in software engineering. It promises to reduce development time, reduce the time and resources required to maintain existing applications, increase code reuse, and provide a competitive advantage to organizations that use it. While the potential benefits and advantages of OOD are real, excessive hype has lead to unrealistic expectations among executives and managers. Even software developers often miss the subtle but profound differences between OOD and classic software development. Many object-oriented methods emphasize the structural aspects of the software system to build and as a consequence, these aspects have a strong influence on the behavioral descriptions. Therefore, object-oriented approaches often exhibit limitations in the modeling of business processes which build the backbone of business applications. In this paper we present a way that should help to bridge the gap between object-orientation and business process modeling. Our approach is based on a combination of object-orientation and workflows and offers five graphical modeling techniques which have clear operational semantics. This enables features like simulating the modeled system or checking whether runs of the system satisfy certain properties and facilitates an integrated development process.

In this paper we present a semantically well founded approach to object-oriented modeling of business processes. We combine object-oriented technologies and ideas from workflow modeling. This leads to a set of description techniques that model all relevant aspects of the system from different views. Our main focus lies on the workflow diagram that allows to directly model the business processes of the application domain from both domain and system experts. This abstract model shows the activities of the business processes and their causal ordering. In our opinion the data flow and the interaction between the system and the user are an integral part of a business process and therefore the workflow diagram also provides means to model these aspects. Besides that, our approach contains four other description techniques (class diagram, instance diagram, state transition diagrams and object behavior charts) that lead to a well integrated, object-oriented model of the business application. In our approach each activity of the workflow diagram is assigned to a method of a concrete instance. So, when an activity should be executed the method of the corresponding instance is called. Object behavior charts allow to further specify what should happen when object methods are called. They provide expressive graphical constructs to model the behavior of object methods and especially the interaction between objects.