03 fse agiledevelopment


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03 fse agiledevelopment

  1. 1. B. Computer Sci. (SE) (Hons.) CSEB233: Fundamentals of Software Engineering Agile Development
  2. 2. Objectives • Discuss • • the concept of agility and agile software development issues Explain the Extreme Programming approach to agile development Describe other agile process models
  3. 3. The Manifesto for Agile Software Development • • ―We are uncovering better ways of developing software by doing it and helping others do it Through this work we have come to value: o o o • o Individuals and interactions over processes and tools Working software over comprehensive documentation Customer collaboration over contract negotiation Responding to change over following a plan That is, while there is value in the items on the right, we value the items on the left more.‖ Kent Beck et al
  4. 4. Agile Development Concept and Issues
  5. 5. What is “Agility”? • Effective (rapid and adaptive) response to change • Effective communication among all stakeholders • Drawing the customer onto the team • Organizing a team so that it is in control of the work performed Yielding … • Rapid, incremental delivery of software
  6. 6. Agility and the Cost of Change
  7. 7. An Agile Process • Is • • • • driven by customer descriptions of what is required (scenarios) Recognizes that plans are short-lived Develops software iteratively with a heavy emphasis on construction activities Delivers multiple ‗software increments‘ Adapts as changes occur
  8. 8. Agility Principles • • Our highest priority is to satisfy the customer through early and continuous delivery of valuable software Welcome changing requirements, even late in development. o • • Agile processes harness change for the customer's competitive advantage Deliver working software frequently, from a couple of weeks to a couple of months, with a preference to the shorter timescale Business people and developers must work together daily throughout the project
  9. 9. Agility Principles • Build projects around motivated individuals. o • • • Give them the environment and support they need, and trust them to get the job done The most efficient and effective method of conveying information to and within a development team is faceto-face conversation Working software is the primary measure of progress. Agile processes promote sustainable development o The sponsors, developers, and users should be able to maintain a constant pace indefinitely
  10. 10. Agility Principles • Continuous • • • attention to technical excellence and good design enhances agility Simplicity – the art of maximizing the amount of work not done – is essential The best architectures, requirements, and designs emerge from self-organizing teams At regular intervals, the team reflects on how to become more effective, then tunes and adjusts its behavior accordingly
  11. 11. Human Factors • • The process molds to the needs of the people and team, not the other way around Key traits must exist among the people on an agile team and the team itself: o o o o o o o Competence Common focus Collaboration Decision-making ability Fuzzy problem-solving ability Mutual trust and respect Self-organization
  12. 12. Agile Development Extreme Programming
  13. 13. Extreme Programming (XP) • The • most widely used agile process, originally proposed by Kent Beck XP Planning Begins with the creation of ―user stories‖ o Agile team assesses each story and assigns a cost o Stories are grouped to for a deliverable increment o A commitment is made on delivery date o After the first increment ―project velocity‖ is used to help define subsequent delivery dates for other increments o
  14. 14. Extreme Programming (XP) • XP Design o o o o Follows the KISS principle Encourage the use of CRC cards (see Chapter 8) For difficult design problems, suggests the creation of ―spike solutions‖— a design prototype Encourages ―refactoring‖—an iterative refinement of the internal program design • XP Coding o o Recommends the construction of a unit test for a store before coding commences Encourages ―pair programming‖ • XP Testing o o All unit tests are executed daily ―Acceptance tests‖ are defined by the customer and excuted to assess customer visible functionality
  15. 15. Extreme Programming (XP) sim p le d esig n CRC c ar d s sp ik e so lut io ns p r o t o t y p es user st o r ies v alues ac c ep t anc e t est c r it er ia it er at io n p lan r ef ac t o r ing p air p r o g r am m ing Release so f t w a r e in cr e m e n t p r o j e ct v e lo cit y co m p u t e d unit t est c o nt inuo us int eg r at io n ac c ep t anc e t est ing
  16. 16. Agile Development Other Agile Process Models
  17. 17. Adaptive Software Development • Originally proposed by Jim Highsmith • ASD‘s distinguishing features Mission-driven planning o Component-based focus o Uses ―time-boxing‖ (See Chapter 24) o Explicit consideration of risks o Emphasizes collaboration for requirements gathering o Emphasizes ―learning‖ throughout the process o
  18. 18. Adaptive Software Development ad ap t iv e c y c le p lanning Req uir em ent s g at her ing uses m issio n st at em ent JA D pro jec t c o nst raint s m ini- sp ec s b asic requirem ent s t im e- b o x ed r elease p lan Release so f t w a r e in cr e m e n t a d j u st m e n t s f o r su b se q u e n t cy cle s c o m p o nent s im p lem ent ed / t est ed f o c us g r o up s f o r f eed b ac k f o r m al t ec hnic al r ev iew s p o st m o r t em s
  19. 19. Dynamic Systems Development Method • • Promoted by the DSDM Consortium (www.dsdm.org) DSDM‘s distinguishing features o o Similar in most respects to XP and/or ASD Nine guiding principles • Active user involvement is imperative. • DSDM teams must be empowered to make decisions. • The focus is on frequent delivery of products. • Fitness for business purpose is the essential criterion for acceptance of deliverables. • Iterative and incremental development is necessary to converge on an accurate business solution. • All changes during development are reversible. • Requirements are baselined at a high level • Testing is integrated throughout the life-cycle.
  20. 20. Dynamic Systems Development Method DSDM Life Cycle (with permission of the DSDM consortium)
  21. 21. Scrum • • Originally proposed by Schwaber and Beedle Scrum‘s distinguishing features o o o o o Development work is partitioned into ―packets‖ Testing and documentation are on-going as the product is constructed Work occurs in ―sprints‖ and is derived from a ―backlog‖ of existing requirements Meetings are very short and sometimes conducted without chairs ―demos‖ are delivered to the customer with the time-box allocated
  22. 22. Scrum
  23. 23. Crystal • Proposed by Cockburn and Highsmith • Crystal‘s distinguishing features Actually a family of process models that allow ―maneuverability‖ based on problem characteristics o Face-to-face communication is emphasized o Suggests the use of ―reflection workshops‖ to review the work habits of the team o
  24. 24. Feature Driven Development • Originally proposed by Peter Coad et al • FDD‘s distinguishing features Emphasis is on defining ―features‖ • a feature ―is a client-valued function that can be implemented in two weeks or less.‖ o Uses a feature template • <action> the <result> <by | for | of | to> a(n) <object> o A features list is created and ―plan by feature‖ is conducted o Design and construction merge in FDD o
  25. 25. Feature Driven Development Reprinted with permission of Peter Coad
  26. 26. Agile Modeling • Originally proposed by Scott Ambler • Suggests a set of agile modeling principles Model with a purpose o Use multiple models o Travel light o Content is more important than representation o Know the models and the tools you use to create them o Adapt locally o
  27. 27. THE END Copyright © 2013 Mohd. Sharifuddin Ahmad, PhD College of Information Technology