Chapter_03_of_software_engineering_book.ppt
- 1. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. 1 Chapter 3 Agile Development Slide Set to accompany Software Engineering: A Practitioner’s Approach, 7/e by Roger S. Pressman Slides copyright © 1996, 2001, 2005, 2009 by Roger S. Pressman For non-profit educational use only May be reproduced ONLY for student use at the university level when used in conjunction with Software Engineering: A Practitioner's Approach, 7/e. Any other reproduction or use is prohibited without the express written permission of the author. All copyright information MUST appear if these slides are posted on a website for student use.
- 2. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. 2 The Manifesto for Agile Software Development “ “We are uncovering better ways of developing We are uncovering better ways of developing software by doing it and helping others do it. software by doing it and helping others do it. Through this work we have come to value: Through this work we have come to value: •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 That is, while there is value in the items on the right, we value the items on the left more.” right, we value the items on the left more.” Kent Beck et al
- 3. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. 3 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
- 4. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. 4 Agility and the Cost of Change
- 5. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. 5 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
- 6. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. 6 Agility Principles - I 1. Our highest priority is to satisfy the customer through early and continuous delivery of valuable software. 2. Welcome changing requirements, even late in development. Agile processes harness change for the customer's competitive advantage. 3. Deliver working software frequently, from a couple of weeks to a couple of months, with a preference to the shorter timescale. 4. Business people and developers must work together daily throughout the project. 5. Build projects around motivated individuals. Give them the environment and support they need, and trust them to get the job done. 6. The most efficient and effective method of conveying information to and within a development team is face–to–face conversation.
- 7. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. 7 Agility Principles - II 7. Working software is the primary measure of progress. 8. Agile processes promote sustainable development. The sponsors, developers, and users should be able to maintain a constant pace indefinitely. 9. Continuous attention to technical excellence and good design enhances agility. 10. Simplicity – the art of maximizing the amount of work not done – is essential. 11. The best architectures, requirements, and designs emerge from self–organizing teams. 12. At regular intervals, the team reflects on how to become more effective, then tunes and adjusts its behavior accordingly.
- 8. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. 8 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: Competence. Common focus. Collaboration. Decision-making ability. Fuzzy problem-solving ability. Mutual trust and respect. Self-organization.
- 9. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. 9 Extreme Programming (XP) The most widely used agile process, originally proposed by Kent Beck XP Planning Begins with the creation of “user stories” Agile team assesses each story and assigns a cost Stories are grouped to for a deliverable increment A commitment is made on delivery date After the first increment “project velocity” is used to help define subsequent delivery dates for other increments
- 10. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. 10 Extreme Programming (XP) XP Design Follows the KIS 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 Recommends the construction of a unit test for a store before coding commences Encourages “pair programming” XP Testing All unit tests are executed daily “Acceptance tests” are defined by the customer and excuted to assess customer visible functionality
- 11. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. 11 Extreme Programming (XP) unit test continuous integration acceptance testing pair programming Release user stories values acceptance test criteria iterationplan simple design CRC cards spike solutions prototypes refactoring softwareincrem ent projectvelocity com puted
- 12. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. 12 Adaptive Software Development Originally proposed by Jim Highsmith ASD — distinguishing features Mission-driven planning Component-based focus Uses “time-boxing” (See Chapter 24) Explicit consideration of risks Emphasizes collaboration for requirements gathering Emphasizes “learning” throughout the process
- 13. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. 13 Adaptive Software Development adaptive cycle planning uses mission statement project constraints basic requirements time-boxed release plan Requirements gathering JAD mini-specs components implemented/tested focus groups for feedback formal technical reviews postmortems softwareincrem ent adjustm entsforsubsequent cycles Release
- 14. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. 14 Dynamic Systems Development Method Promoted by the DSDM Consortium (www.dsdm.org) DSDM—distinguishing features 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.
- 15. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. 15 Dynamic Systems Development Method DSDM Life Cycle (with permission of the DSDM consortium)
- 16. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. 16 Scrum Originally proposed by Schwaber and Beedle Scrum—distinguishing features 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
- 17. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. 17 Scrum ScrumProcessFlow(usedwithperm ission)
- 18. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. 18 Crystal Proposed by Cockburn and Highsmith Crystal—distinguishing features Actually a family of process models that allow “maneuverability” based on problem characteristics Face-to-face communication is emphasized Suggests the use of “reflection workshops” to review the work habits of the team
- 19. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. 19 Feature Driven Development Originally proposed by Peter Coad et al FDD—distinguishing features Emphasis is on defining “features” • a feature “is a client-valued function that can be implemented in two weeks or less.” Uses a feature template • <action> the <result> <by | for | of | to> a(n) <object> A features list is created and “plan by feature” is conducted Design and construction merge in FDD
- 20. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. 20 Feature Driven Development Reprinted with permission of Peter Coad Reprinted with permission of Peter Coad
- 21. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. 21 Agile Modeling Originally proposed by Scott Ambler Suggests a set of agile modeling principles Model with a purpose Use multiple models Travel light Content is more important than representation Know the models and the tools you use to create them Adapt locally