14-1 © Prentice Hall, 2004 Chapter 14: OOSAD Implementation and Operation (Adapted) Object-Oriented Systems Analysis and Design Joey F. George, Dinesh Batra, Joseph S. Valacich, Jeffrey A. Hoffer

Chapter © Prentice Hall, 2004 Outline System Implementation Concept Coding, Testing, Converting, Training Steps Installation strategies

Chapter © Prentice Hall, 2004 System Implementation Concept Activities that transform design into a working system and set the system into the production stage. In OO methodology, these activities fall mostly into the construction and transition stages. Note: As opposed to common sense, coding is part of implementation - not design.

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Chapter © Prentice Hall, 2004 Coding Translation of physical design specifications into working computer code Coding involves use of programming languages such as Java or Visual Basic eXtreme programming – an intensive coding and testing approach involving two-person teams and customer involvement

Chapter © Prentice Hall, 2004 Reuse The use of previously written software resources, especially objects and components, in new applications Results in great savings of system development time Object-oriented systems are very conducive to reuse.

Chapter © Prentice Hall, 2004 Approaches to Reuse Ad hoc – individual, unplanned use Facilitated – use informally managed and disseminated by expert guru evangelists Managed – organizationally enforced reuse policies and practices Designed – reusable components developed and maintained in-house Cost and commitment low high

Chapter © Prentice Hall, 2004 Software Testing Manual and automated procedures for validating correctness of program code, including syntactical and execution issues Testing Syntax – grammatical rules applied to programming languages Testing Execution – logic and performance of the software during operation Note: Bug-free software remains a dream!

Chapter © Prentice Hall, 2004 Tests can be manual or automated, and may or may not involve code execution.

Chapter © Prentice Hall, 2004 Tests Without Program Execution Inspections (manual) – Participants examine program code for predictable, language-specific errors Syntax checking (automated) – Compiler or interpreter tests source code for grammatical errors while translating to executable format

Chapter © Prentice Hall, 2004 Manual Tests With Program Execution Desk checking – trace through the logic of the code, identifying possible logical errors Walkthroughs – Like desk-checking, but in a group-oriented, more structured process

Chapter © Prentice Hall, 2004 Automated Tests With Program Execution Unit tests – a module tested in isolation for internal consistency Integration tests – testing all modules and components of the application together for interaction compatibilities System tests – testing all programs and applications together to ensure performance and reliability Acceptance tests – user-satisfaction tests

Chapter © Prentice Hall, 2004 A test case is a specific scenario of transactions, queries, or navigation paths that represent a typical, abnormal, or critical use of the system. Allows repeated testing with each application change

Chapter © Prentice Hall, 2004 Installation The process of turning over from the old information system to the new one. Types: – Direct – Parallel – Single location – Phased

Chapter © Prentice Hall, 2004 Direct – Cold turkey, low cost, greater impact of errors.

Chapter © Prentice Hall, 2004 Parallel – old and new coexist, minimize error impact, high cost in system resources.

Chapter © Prentice Hall, 2004 Single Location – Pilot approach, allows learning and minimizes error impact, lower resource demand than parallel, difficult to coordinate and maintain.

Chapter © Prentice Hall, 2004 Phased – Staged and incremental, supports phased system development, minimize error impact, difficult to coordinate old components and new components.

Chapter © Prentice Hall, 2004 Types of Documentation System – detailed information about a system’s design specifications, its inner workings, and its functionality. User – written or other visual information about an application system, how it works, and how to use it. Internal – comments in source code, generated during the coding process or automatically. External – outcomes of all structured diagrams, including use cases, design classes, activity and sequence diagrams, etc.

Chapter © Prentice Hall, 2004 User Training Providing on-going educational and problem- solving assistance to information systems users. Training and support material and jobs must be designed along with the associated information systems. User documentation is often in the form of online help, sometimes with Web connections for further information.

Chapter © Prentice Hall, 2004 Training methods can be interpersonal, manual, or automated.

Chapter © Prentice Hall, 2004 Help Desks and Information Centers Help desk – a single point of contact for all user inquiries and problems about a particular information system or for all users in a particular department Information center – an organizational unit whose mission is to support users in exploiting information technology

Chapter © Prentice Hall, 2004