DEV475 Mastering Object-Oriented Analysis and Design with UML ...

Module 6 - Use-Case AnalysisReview: Why Use Analysis Mechanisms?Review: Why Use Analysis Mechanisms?Oh no! I found a group of classes thathas persistent data. How am Isupposed to design these things if Idon’t even know what database we aregoing to be using?That is why we have a persistenceanalysis mechanism. We don’tknow enough yet, so we canbookmark it and come back to itlater.Analysis mechanisms are used during analysis to reduce the complexity ofanalysis, and to improve its consistency by providing designers with ashorthand representation for complex behavior.Mastering Object Oriented Analysis and Design with UMLCopyright © 2003 Rational Software, all rights reserved 53An analysis mechanism represents a pattern that constitutes a common solution to acommon problem. These mechanisms may show patterns of structure, patterns ofbehavior, or both. They are used during Analysis to reduce the complexity ofAnalysis, and to improve its consistency by providing designers with a shorthandrepresentation for complex behavior. Analysis mechanisms are primarily used as“placeholders” for complex technology in the middle and lower layers of thearchitecture. By using mechanisms as “placeholders” in the architecture, thearchitecting effort is less likely to become distracted by the details of mechanismbehavior.Mechanisms allow the Analysis effort to focus on translating the functionalrequirements into software concepts without bogging down in the specification ofrelatively complex behavior needed to support the functionality but which is notcentral to it. Analysis mechanisms often result from the instantiation of one or morearchitectural or analysis patterns. Persistence provides an example of analysismechanisms. A persistent object is one that logically exists beyond the scope of theprogram that created it. During analysis, we do not want to be distracted by thedetails of how we are going to achieve persistence.This gives rise to a “persistence”analysis mechanism that allows us to speak of persistent objects and capture therequirements we will have on the persistence mechanism without worrying aboutwhat exactly the persistence mechanism will do or how it will work.Analysis mechanisms are typically, but not necessarily, unrelated to the problemdomain, but instead are "computer science" concepts. As a result, they typicallyoccupy the middle and lower layers of the architecture. They provide specificbehaviors to a domain-related class or component, or correspond to theimplementation of cooperation between classes and/or components.6 - 53