Unit_1_Agile development.pdf about the script of software
- 2. Looping Outline What is Agility? Agile Process Agility Principles Where agile methodology not work? Agile Process Models • Extreme Programming (XP) • Adaptive Software Development (ASD) • Dynamic Systems Development Method (DSDM) • Scrum • Feature Driven Development (FDD) • Crystal • Agile Modelling (AM)
- 3. Agility The ability to create and respond to change in order to profit in a unstable global business environment. The ability to quickly reprioritize use of resources when requirements, technology, and knowledge shift. A very fast response to sudden market changes and emerging threats by intensive customer interaction. Use of evolutionary, incremental, and iterative delivery to converge on an optimal customer solution. Maximizing BUSINESS VALUE with right sized, just- enough, and just-in-time processes and documentation. Agility is ability to move quickly and easily. It is a property consisting of quickness, lightness, & ease of movement.
- 4. What is Agility? Cont. Current Functionality Change Request Effective response to change Effective communication among all stakeholders Organizing a team so that it is in control to perform the work Customer Drawing the customer onto the team Eliminate the “us and them” attitude Development Team Rapid and Incremental delivery of software
- 5. Agile Process Agile software process addresses few assumptions An agile process must adapt incrementally. To accomplish incremental adaptation, an agile team requires customer feedback (so that the appropriate adaptations can be made). Analysis, design, construction and testing are not as predictable as we might like. Difficulty in predicting changes of requirements and customer priorities. For many types of software; design and construction are interleaved (mixed).
- 6. Agility Principles Highest priority is to satisfy the customer through early & continuous delivery of software Welcome changing requirements Deliver working software frequently Business people and developers must work together Build projects around motivated individuals Emphasize face-to-face conversation Working software is the measure of progress Continuous attention to technical excellence and good design Simplicity – the art of maximizing the amount of work done The best designs emerge from self-organizing teams The team tunes and adjusts its behaviour to become more effective
- 7. Where agile methodology not work Project plan & requirements are clear & unlikely to change Unclear understanding of Agile Approach among Teams Big Enterprises where team collaboration is tough
- 8. Agile Process Models Extreme Programming (XP) Adaptive Software Development (ASD) Dynamic Systems Development Method (DSDM) Feature Driven Development (FDD) Crystal Agile Modelling (AM)
- 9. Extreme Programming (XP) The most widely used approach to agile software development A variant of XP called Industrial XP (IXP) has been proposed to target process for large organizations It uses object oriented approach as its preferred development model XP Values Communication: To achieve effective communication, it emphasized close & informal (verbal) collaboration between customers and developers Simplicity: It restricts developers to design for immediate needs not for future needs Feedback: It is derived from three sources the implemented software, the customer and other software team members, it uses Unit testing as primary testing Courage: It demands courage (discipline), there is often significant pressure to design for future requirements, XP team must have the discipline (courage) to design for today Respect: XP team respect among members
- 10. The XP Process It considers four framework activities 1. Planning 2. Design 3. Coding 4. Testing Planning User Stories • Customers assigns value (priority) • Developers assigns cost (number of development weeks) Project velocity • Computed at the end of first release • Number of stories implemented in first release • Estimates for future release • Guard against over-commitment
- 11. The XP Process cont. • Keep-it-Simple (Design of extra functionality is discouraged) • Preparation of CRC card is work project • CRC cards identify and organize object oriented classes • Spike Solutions (in case of difficult design problem is encountered) • Operational prototype intended to clear confusion • Refactoring • Modify internals of code, No observable change Design CRC card Coding • Develops a series of Unit test for stories included in current release • Complete code perform unit-test to get immediate feedback • XP recommend pair-programming, “Two heads are better than one” • Integrate code with other team members, this “continuous integration” helps to avoid compatibility & interfacing problems, “smoke testing” environment to uncover errors early • Unit test by developers & fix small problems • Acceptance tests - Specified by customer • This encourages regression testing strategy whenever code is modified Testing
- 12. What is Scrum? A scrum is a method of restarting play in rugby that involves players packing closely together with their heads down and attempting to gain possession of the ball. It is a lightweight process framework. Lightweight means the overhead of the process is kept as small as possible in order to maximize the productivity. Sprint Product Product Backlog Product Owner Scrum is an agile process model which is used for developing the complex software systems. Daily Scrum Meeting
- 13. Scrum framework at a glance Inputs from Customers, Team, Managers Product Owner Product Backlog Sprint Planning Meeting Sprint Backlog Scrum Master Daily Scrum Meetings Sprint Review Finished Work Sprint Retrospective Team Selects starting at top as much as it can commit to deliver by end of sprint Prioritized list of what is required: features, bugs to fix... Sprint end date and team deliverable do not change
- 14. Scrum cont. Backlog It is a prioritized list of project requirements or features that must be provided to the customer. The items can be included in the backlog at any time. The product manager analyses this list and updates the priorities as per the requirements. Sprint These are the work units that are needed to achieve the requirements mentioned in the backlogs. Typically the sprints have fixed duration or time box (of 2 to 4 weeks, 30 days). Change are not introduced during the sprint. Thus sprints allow the team members to work in stable and short-term environment
- 15. Scrum Meetings There are 15 minutes daily meetings to report the completed activities, obstacles and plan for next activities. Following are three questions that are mainly discussed during the meetings. 1. What are the tasks done since last meeting ? 2. What are the issues that team is facing ? 3. What are the next activities that are planned? The scrum master leads the meeting and analyses the response of each team member. Scrum meeting helps the team to uncover potential problems as early as possible It leads to “knowledge socialization” & promotes “self-organizing team structure” Demo Scrum cont. Deliver software increment to customer Implemented functionalities are demonstrated to the customer
- 16. Adaptive Software development (ASD) This is a technique for building complex software systems using iterative approach. ASD focus on working in collaboration and team self-organization. ASD incorporates three phases 1. Speculation, 2. Collaboration & 3. Learning Speculation The adaptive cycle planning is conducted. In this cycle planning mainly three types of information is used Customer’s mission statement Project constraints (Delivery date, budgets etc…) Basic requirements of the project
- 17. Adaptive Software development (ASD) cont. Collaboration In this, collaboration among the members of development team is a key factor. For successful collaboration and coordination it is necessary to have following qualities in every individual Learning Emphasize is on learning new skills and techniques. There are three ways by which the team members learn Assist each other without resentment (offense) Work hard Posses the required skill set Communicate problems and help each other Criticize without any hate Focus groups The feedback from the end-users is obtained. Formal technical review This review is conducted for better quality. Postmortems Team analyses its own performance and makes appropriate improvements.
- 18. Dynamic Systems Development Methods (DSDM) Various phases of this life cycle model Feasibility study: By analysing the business requirements and constraints the viability of the application is determined Business study: The functional and informational requirements are identified and then the business value of the application is determined Functional model iteration: The incremental approach is adopted for development Design and build iteration: If possible design and build activities can be carried out in parallel Implementation: The software increment is placed in the working environment
- 19. Feature Driven Development (FDD) It is practical process model for object oriented software engineering In FDD, the feature means client valued function.
- 20. Feature Driven Development (FDD) cont. 1. Develop overall model The high-level walkthrough of scope and detailed domain walkthrough are conducted to create overall models. 2. Build feature list List of features is created and expressed in the following form <action> the <result> <by for of to> a(n) <object> For Ex. “Display product-specifications of the product” 3. Plan by feature After completing the feature list the development plan is created Design by feature For each feature the sequence diagram is created Build by feature Finally the class owner develop the actual code for their classes