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Chapter 17 Current Trends in System Development

Chapter 17 Current Trends in System Development. Systems Analysis and Design in a Changing World, 5th Edition. Learning Objectives. Explain the foundations for the adaptive development methodologies List and describe the features of the Unified Process system development methodology

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Chapter 17 Current Trends in System Development

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  1. Chapter 17 Current Trends in System Development Systems Analysis and Design in a Changing World, 5th Edition

  2. Learning Objectives • Explain the foundations for the adaptive development methodologies • List and describe the features of the Unified Process system development methodology • List and describe the features of Agile Modeling • Compare and contrast the features of Extreme Programming and Scrum development • Explain the importance of Model-Driven Architecture on enterprise-level development • Describe frameworks and components, the process by which they are developed, and their impact on system development

  3. Overview • The IS discipline is dynamic and always changing • More complex system requirements have necessitated a whole new set of tools • The Unified Process (UP)‏ • Radical, adaptive approaches, including Agile Development, Extreme Programming, and Scrum • Model-Driven Architecture for enterprise-level systems • Object frameworks and components to increase productivity and quality

  4. Software Principles and Practices • Ubiquitous computing is the current trend in our society • Using computer technology in every aspect of our lives • The effort to develop current solutions is demanding • Current trends in modeling and development processes use five important principles • Abstraction • Process of extracting core principles from a set of facts or statement • Example: Metamodels describe the characteristics of another model • Models and modeling • An abstraction of something in the real world, representing a particular set of properties

  5. Software Principles and Practices (cont’d)‏ • Patterns • Standard solutions to a given problem or templates that can be applied to a problem • Reuse • Building standard solutions and components that can be used over and over again • Methodologies • A process—including the rules, guidelines, and techniques—that defines how systems are built

  6. Adaptive Approaches to Development • Opposite end of spectrum from predictive approaches (recall Chapter 2)‏ • Allow for uncertainty • Use empirical controls, not predictive controls • Describe processes that are variable and unpredictable • Monitor progress and make corrections on the fly

  7. Adaptive Approaches to Development— Characteristics • Less emphasis on up-front analysis, design, and documentation • More focus on incremental development • More user involvement in project teams • Reduced detailed planning • Used for near-term work phases only • Tightly control schedules by fitting work into discrete time boxes • More use of small work teams that are self-organizing

  8. The Unified Process (UP)‏ • Object-oriented system development methodology (system development process)‏ • Offered by Rational/IBM, UP developed by Booch, Rumbaugh, and Jacobson • UP should be tailored to organizational and project needs • Highly iterative life cycle • Project will be use-case driven and modeled using UML

  9. The Unified Process Life Cycle • UP life cycle • Includes four phases which consist of iterations • Iterations are “mini-projects” • Inception – develop and refine system vision • Elaboration – define requirements and design and implement core architecture • Construction – continue design and implementation of routine, less risky parts • Transition – move the system into operational mode

  10. The Unified Process Life Cycle Figure 17-1

  11. UP Phases and Objectives Figure 17-2

  12. The UP Disciplines • UP defines disciplines used within each phase • Discipline – set of functionally related development activities • Each iteration includes activities from all disciplines • Activities in each discipline produce artifacts – models, documents, source code, and executables • Learning CIS/MIS means learning techniques from these disciplines • Six main UP development disciplines • Business modeling, requirements, design, implementation, testing, and deployment • Three additional support disciplines • Project management, configuration and change management, and environment

  13. The UP Disciplines (cont’d)‏ • Six main UP development disciplines • Business modeling, requirements, design, implementation, testing, and deployment • Three additional support disciplines • Project management, configuration and change management, and environment

  14. UP Disciplines Used in Varying Amounts in Each Iteration Figure 17-3

  15. UP Life Cycle Model Showing Phases, Iterations, and Disciplines Figure 17-4

  16. The Agile Development Philosophy and Modeling • Agile Development Principles • A philosophy and set of guidelines for developing software in an unknown, rapidly changing environment • Requires agility – being able to change direction rapidly, even in the middle of a project • Agile Modeling Principles • A philosophy about how to build models, some of which are formal and detailed and others are sketchy and minimal

  17. Adaptive Methodologies Using Agile Modeling Figure 17-5

  18. The Agile Development Philosophy and Values • Responding to change over following a plan • An agile project is chaordic – both chaotic and ordered • Individuals and interactions over processes and tools • Working software over comprehensive documentation • Customer collaboration over contract negotiation

  19. Agile Modeling Principles • AM is about doing the right kind of modeling at the right level of detail for the right purposes • Use models as a means to an end instead of building models as end deliverables • Does not dictate which models to build or how formal to make those models • Has basic principles to express the attitude that developers should have as they develop software

  20. Agile Modeling Principles Figure 17-6

  21. Agile Modeling Practices Figure 17-7

  22. Extreme Programming (XP)‏ • An adaptive, agile development methodology created in the mid-1990s • Takes proven industry best practices and focuses on them intensely • Combines those best practices (in their intense form) in a new way to produce a result that is greater than the sum of the parts

  23. XP Core Values • Communication • In open, frequent verbal discussions • Simplicity • In designing and implementing solutions • Feedback • On functionality, requirements, designs, and code • Courage • In facing choices such as throwing away bad code or standing up to a too-tight schedule

  24. Some XP Practices • Planning • Users develop a set of stories to describe what the system needs to do • Testing • Tests are written before solutions are implemented • Pair programming • Two programmers work together on designing, coding, and testing • Simple designs • “KISS” and design continuously

  25. Some XP Practices (cont’d)‏ • Refactoring • Improving code without changing what it does • Owning the code collectively • Anyone can modify any piece of code • Continuous integration • Small pieces of code are integrated into the system daily or more often • System metaphor • Guides members towards a vision of the system

  26. Some XP Practices (cont’d)‏ • On-site customer • Intensive user/customer interaction required • Small releases • Produce small and frequent releases to user/customer • Forty-hour work week • Project should be managed to avoid burnout • Coding standards • Follow coding standards to ensure flexibility

  27. XP Core Values and Practices Figure 17-8

  28. XP Project Activities • System-level activities • Occur once during each development project • Involve creating user stories to planning releases • Release-level activities • Cycle multiple times – once for each release • Are developed and tested in a period of no more than a few weeks or months • Iteration-level activities • Code and test a specific functional subset in a few days or weeks

  29. XP Development Approach Figure 17-9

  30. Scrum • A quick, adaptive, and self-organizing development methodology • Named after rugby’s system for getting an out-of-play ball into play • Responds to a current situation as rapidly and positively as possible • A truly empirical process control approach to developing software

  31. Scrum Philosophy • Responsive to a highly changing, dynamic environment • Focuses primarily on the team level • Team exerts total control over its own organization and work processes • Uses a product backlog as the basic control mechanism • Prioritized list of user requirements used to choose work to be done during a Scrum project

  32. Scrum Organization • Product owner • The client stakeholder for whom a system is being built • Maintains the product backlog list • Scrum master • Person in charge of a Scrum project • Scrum team or teams • Small group of developers • Set their own goals and distribute work among themselves

  33. Scrum Practices • Sprint • The basic work process in Scrum • A time-controlled mini-project • Firm 30-day time box with a specific goal or deliverable • Parts of a sprint • Begins with a one-day planning session • A short daily Scrum meeting to report progress • Ends with a final half-day review

  34. Scrum Software Development Process Figure 17-10

  35. Project Management and Adaptive Methodologies • Project time management • Smaller scope and focused on each iteration • Realistic work schedules • Project scope management • Users and clients are responsible for the scope • Scope control consists of controlling the number of iterations • Project cost management • More difficult to predict because of unknowns • Project communication management • Critical because of open verbal communication and collaborative work

  36. Project Management and Adaptive Methodologies (cont’d)‏ • Project quality management • Continual testing and refactoring must be scheduled • Project risk management • High-risk aspects addressed in early iterations • Project human resource management • Teams organize themselves • Project procurement management • Integrating purchased elements into the overall project • Verifying quality of components • Satisfying contractual commitments

  37. Model-Driven Architecture • Model-Driven Architecture (MDA) is an OMG (Object Management Group) initiative • Built on the principles of abstraction, modeling, reuse, and patterns • Provides companies with a framework to identify and classify all system development work being done in an enterprise • MDA extracts current systems features and information and combines them into a platform independent model (PIM)‏

  38. Model-Driven Architecture (cont’d)‏ • Platform-independent model (PIM)‏ • Describes system characteristics that are not specific to any deployment diagram • Uses UML • Platform-specific model (PSM)‏ • Describes system characteristics that include deployment platform requirements • A set of standard transformations by the OMG move a PSM to a PIM

  39. Software Development and MDA Figure 17-11

  40. Metamodels and Transitions between PIM, PSM, and Code Figure 17-12

  41. Partial Metamodel of UML Class Diagram Figure 17-13

  42. Object Frameworks • A set of classes that are designed to be reused in a variety of programs • The classes within an object framework are called foundation classes • Can be organized into one or more inheritance hierarchies • Application-specific classes can be derived from existing foundation classes

  43. Object Framework Types • User-interface classes • Commonly used objects within a GUI • Generic data structure classes • Linked lists, binary trees, and so on, and related processing operations • Relational database interface classes • Classes to create and perform operations on tables • Classes specific to an application area • For use in a specific industry or application type

  44. Impact on Design and Implementation • Frameworks must be chosen early in the project • Systems design must conform to specific assumptions about application program structure and operation that the framework imposes • Design and development personnel must be trained to use a framework effectively • Multiple frameworks might be required, necessitating early compatibility and integration testing

  45. Components • Software modules that are fully assembled and ready to use • Reusable packages of executable code • Have well-defined interfaces to connect them to clients or other components • Public interfaces and encapsulated implementation • Standardized and interchangeable • Updating a single component does not require relinking, recompiling, and redistributing an entire application

  46. Component Standards and Infrastructure • Interoperability of components requires standards to be developed and readily available • Components might also require standard support infrastructure • Software components have more flexibility when they can rely on standard infrastructure services to find other components • Networking standards are required for components in different locations

  47. CORBA and COM+ • CORBA (Common Object Request Broker Architecture) is a standard for software component connection and interaction developed by the OMG • An object request broker (ORB) provides component directory and communication services • The Internet Inter-ORB Protocol (IIOP) is used to communicate among objects and ORBs • Component Object Model Plus (COM+) is a standard for software component connection and interaction developed by Microsoft

  48. Enterprise JavaBeans • Part of the Java programming language’s extensive object framework (JDK)‏ • A JavaBean can execute on a server and communicate with clients and other components using CORBA • A JavaBean implements the required component methods and follows the required naming conventions of the JavaBean standard • Platform independent

  49. Components and the Development Life Cycle • Component purchase and reuse is a viable approach to speeding completion of a system • Purchased components can form all or part of a newly developed or re-implemented system • Components can be designed in-house and deployed in a newly developed or re-implemented system

  50. Using Purchased Components— Implications • Standards and support software of purchased components must become part of the technical requirements definition • A component’s technical support requirements restrict the options considered during software architectural design

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