VC++第三章.ppt

Chapter 3 Case Studies Introduction 3.1 What is and isn’t Covered in the Case Studies? 3.2 Case Study Strategy: Iterative Development + Iterative Learning 3.3 Case One: The NextGen POS System 3.4 Case Two: The Monopoly Game System Introduction These case study problems were chosen because they’re familiar to many people, yet rich with complexity and interesting design problems. That allows us to concentrate on learning fundamental OOA/D, requirements analysis, UML and patterns, rather than explaining the problems. 3.1 What is and isn’t Coveredin the Case Studies? Generally, applications include UI elements, core application logic, database access, and collaboration with external software or hardware components. A typical object-oriented information system is designed in terms of several architectural layers or subsystems. The following is not a complete list, but provides an example. User Interface—graphical interface; windows. Application Logic and Domain Objects—software objects representing domain concepts (for example, a software class named Sale) that fulfill application requirements. Technical Services—general purpose objects and subsystems that provide supporting technical services, such as interfacing with a database or error logging. These services are usually application-independent and reusable across several system. OOA/D is generally most relevant for modeling the application logic and technical service layers. The NextGen case study primarily emphasizes the problem domain objects, allocating responsibilities to them to fulfill the requirements of the application. In this design approach, the UI layer has very little responsibility. 3.2 Case Study Strategy: Iterative Development+ Iterative Learning This book is organized to show an iterative development strategy. OOA/D is applied to the NextGen POS system in multiple iterations; the first iteration is for some core functions. Later iterations expand the functionality of the system. 3.3 Case One