tailieunhanh - Java™ How to Program ( Deitel - Deitel) - Phần 5

Tham khảo sách 'java™ how to program ( deitel - deitel) - phần 5', công nghệ thông tin, kỹ thuật lập trình phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | life cycle models exist each with its own preferences and specifications for when and how often software engineers should perform each of these stages. Waterfall models perform each stage once in succession whereas iterative models may repeat one or more stages several times throughout a product s life cycle. The analysis stage of the software life cycle focuses on defining the problem to be solved. When designing any system one must solve the problem right but of equal importance one must solve the right problem. Systems analysts collect the requirements that indicate the specific problem to solve. Our requirements document describes the requirements of our ATM system in sufficient detail that you do not need to go through an extensive analysis stageit has been done for you. To capture what a proposed system should do developers often employ a technique known as use case modeling. This process identifies the use cases of the system each of which represents a different capability that the system provides to its clients. For example ATMs typically have several use cases such as View Account Balance Withdraw Cash Deposit Funds Transfer Funds Between Accounts and Buy Postage Stamps. The simplified ATM system we build in this case study allows only the first three use cases. Each use case describes a typical scenario for which the user uses the system. You have already read descriptions of the ATM system s use cases in the requirements document the lists of steps required to perform each transaction type . balance inquiry withdrawal and deposit actually described the three use cases of our ATM View Account Balance Withdraw Cash and Deposit Funds. Use Case Diagrams We now introduce the first of several UML diagrams in the case study. We create a use case diagram to model the interactions between a system s clients in this case study bank customers and its use cases. The goal is to show the kinds of interactions users have with a system without providing the .