1. Coming up: The Manifesto for Agile Software Development 1 Software Engineering: A Practitioner’s Approach, 7/e Chapter 3 Agile Development Software Engineering: A Practitioner’s Approach, 7/e Chapter 3 Agile Development copyright © 1996, 2001, 2005 R.S. Pressman & Associates, Inc. For University Use Only May be reproduced ONLY for student use at the university level when used in conjunction with Software Engineering: A Practitioner's Approach. Any other reproduction or use is expressly prohibited.

2. Coming up: What is “Agility”? 2 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: Individuals and interactions over processes and toolsIndividuals and interactions over processes and tools Working software over comprehensive documentationWorking software over comprehensive documentation Customer collaboration over contract negotiationCustomer collaboration over contract negotiation Responding to change over following a planResponding 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.” agilemanifesto.org Kent Beck et al

3. Coming up: An Agile Process 3 What is “Agility”? Effective (rapid and adaptive) response to change Effective (rapid and adaptive) response to change Effective communication among all stakeholders Effective communication among all stakeholders Drawing the customer onto the team Drawing the customer onto the team Organizing a team so that it is in control of the work performed Organizing a team so that it is in control of the work performed Yielding … Rapid, incremental delivery of software Rapid, incremental delivery of software

4. Coming up: Extreme Programming (XP) 4 An Agile Process Is driven by customer descriptions of what is required (scenarios) Is driven by customer descriptions of what is required (scenarios) Recognizes that plans are short-lived Recognizes that plans are short-lived Develops software iteratively with a heavy emphasis on construction activities Develops software iteratively with a heavy emphasis on construction activities Delivers multiple ‘software increments’ Delivers multiple ‘software increments’ Adapts as changes occur Adapts as changes occur

5. Coming up: Extreme Programming (XP) 5 Extreme Programming (XP) The second most widely used agile process, originally proposed by Kent Beck The second most widely used agile process, originally proposed by Kent Beck XP Planning XP Planning Begins with the creation of “user stories” Begins with the creation of “user stories” Agile team assesses each story and assigns a cost Agile team assesses each story and assigns a cost Stories are grouped to for a deliverable increment Stories are grouped to for a deliverable increment A commitment is made on delivery date A commitment is made on delivery date After the first increment “project velocity” is used to help define subsequent delivery dates for other increments After the first increment “project velocity” is used to help define subsequent delivery dates for other increments

6. Coming up: Extreme Programming (XP) 6 Extreme Programming (XP) XP Design XP Design Follows the KIS principle Follows the KIS principle Encourage the use of CRC cards (see Chapter 8) Encourage the use of CRC cards (see Chapter 8) For difficult design problems, suggests the creation of “spike solutions”—a design prototype For difficult design problems, suggests the creation of “spike solutions”—a design prototype Encourages “refactoring”—an iterative refinement of the internal program design Encourages “refactoring”—an iterative refinement of the internal program design XP Coding XP Coding Recommends the construction of a unit test for a store before coding commences Recommends the construction of a unit test for a store before coding commences Encourages “pair programming” Encourages “pair programming” XP Testing XP Testing All unit tests are executed daily All unit tests are executed daily “Acceptance tests” are defined by the customer and excuted to assess customer visible functionality “Acceptance tests” are defined by the customer and excuted to assess customer visible functionality Skipping this slide because we will talk in detail about XP

7. Coming up: Dynamic Systems Development Method 7 Extreme Programming (XP) Skipping this slide because we will talk in detail about XP

8. Coming up: Dynamic Systems Development Method 8 Dynamic Systems Development Method Promoted by the DSDM Consortium (www.dsdm.org) Promoted by the DSDM Consortium (www.dsdm.org)www.dsdm.org DSDM—distinguishing features DSDM—distinguishing features Similar in most respects to XP and/or ASD Similar in most respects to XP and/or ASD Nine guiding principles Nine guiding principles Active user involvement is imperative. Active user involvement is imperative. DSDM teams must be empowered to make decisions. DSDM teams must be empowered to make decisions. The focus is on frequent delivery of products. The focus is on frequent delivery of products. Fitness for business purpose is the essential criterion for acceptance of deliverables. 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. Iterative and incremental development is necessary to converge on an accurate business solution. All changes during development are reversible. (configuration management) All changes during development are reversible. (configuration management) Requirements are baselined at a high level Requirements are baselined at a high level Testing is integrated throughout the life-cycle. Testing is integrated throughout the life-cycle.

9. Coming up: Scrum 9 Dynamic Systems Development Method DSDM Life Cycle (with permission of the DSDM consortium) Prototype Design Protoytype for requirements Implement/Deplo y/Train Will it work?

10. Coming up: Scrum 10 Scrum Originally proposed by Schwaber and Beedle Originally proposed by Schwaber and Beedle Scrum—distinguishing features Scrum—distinguishing features Development work is partitioned into “packets” Development work is partitioned into “packets” Testing and documentation are on-going as the product is constructed Testing and documentation are on-going as the product is constructed Work occurs in “sprints” and is derived from a “backlog” of existing requirements Work occurs in “sprints” and is derived from a “backlog” of existing requirements Meetings are very short and sometimes conducted without chairs Meetings are very short and sometimes conducted without chairs “demos” are delivered to the customer with the time-box allocated “demos” are delivered to the customer with the time-box allocated Currently seems to have overtaken XP as most popular Currently seems to have overtaken XP as most popular

11. Coming up: Others 11Scrum

12. Others Crystal Crystal A family of methods to choose from (based on needs) A family of methods to choose from (based on needs) Colocation to facilitate constant communication Colocation to facilitate constant communication Frequent code delivery Frequent code delivery Feature Driven Development Feature Driven Development Design and develop feature by feature Design and develop feature by feature Frequent code delivery Frequent code delivery Adaptive Software Development (ASD) Adaptive Software Development (ASD) Speculation – plan increments Speculation – plan increments Collaborate – discuss requirements and plan Collaborate – discuss requirements and plan Learn - implement and learn the truth Learn - implement and learn the truth Agile Unified Process – Based on UML Agile Unified Process – Based on UML Same phases as RUP, but more iteration during each phase Same phases as RUP, but more iteration during each phase 12

13. Agile Idea Frequent idea: Fix time, not features Frequent idea: Fix time, not features 13 Functionality TimeResourcesFunctionality TimeResources Agile Prescriptive FIXED VARIABLE

14. Criticisms Lack of structure and necessary documentation Lack of structure and necessary documentation Only works with senior-level developers Only works with senior-level developers Incorporates insufficient software design Incorporates insufficient software design Requires meetings at frequent intervals at enormous expense to customers Requires meetings at frequent intervals at enormous expense to customers Requires too much cultural change to adopt Requires too much cultural change to adopt Can lead to more difficult contractual negotiations Can lead to more difficult contractual negotiations Can be very inefficient— maybe code things multiple times as they changeif the requirements for one area of code change through various iterations, the same programming may need to be done several times over. Whereas if a plan were there to be followed, a single area of code is expected to be written once. Can be very inefficient— maybe code things multiple times as they changeif the requirements for one area of code change through various iterations, the same programming may need to be done several times over. Whereas if a plan were there to be followed, a single area of code is expected to be written once. Hard to develop realistic estimates of work effort because at the beginning of the project no one knows the entire scope/requirements Hard to develop realistic estimates of work effort because at the beginning of the project no one knows the entire scope/requirements Agile is feature driven, non-functional quality attributes are hard to be placed as user stories Agile is feature driven, non-functional quality attributes are hard to be placed as user stories Can increase the risk of scope creep due to lack of detailed requirements Can increase the risk of scope creep due to lack of detailed requirements 14 Source: Wikipedia