AGILE SOFTWARE DEVELOPMENT
Abstract: Software development which can be delivered fast, quick adaptation to requirements and collecting feedback on required information. The agile software methods and development is practices based approach empowered with values, principles and practices which make the software development process more easy and in faster time.
Agile methods which encompasses individual methods like Extreme programming,
Feature Driven Development, Scrum, etc are more coming into the commercial and academic worlds.
Agility refers to the quality of being agile. Internet software industry and Mobile and wireless application development industry are looking for a very good approach of software development. Conventional software development methods have completely closed the requirements process before analysis and design process. As, this approach is not always feasible and compatible with all other projects. In contrast to the conventional approaches, Agile methods allow developers to make late changes in the requirement specification document.
The focus of the Agile software development as given by “Agile Software Development Manifesto” is presented in the following:
o Indivduals and interactions over processes and tools
o Working software over comprehensive documentation.
o Customer collaboration over contract negotiation
o Responding to change over following a plan
1) There is vital importance of communication between the individual who are in development team, since development centers are located at different places. The necessity of interaction between Individuals over different tools and different versions and processes is very vital.
2) The only objective of software development team is to continuously deliver the working software for the customers. New releases must be produced for frequent intervals. The developers try to keep the code simple, straight forward and technically as advanced as possible and will try to lessen the documentation.
3) The relationship between developers and the stakeholders is most important as the pace and the size of the project grows. The cooperation and negotiation between clients and the developers is the key for the relationship. Agile methods are using in maintaining good relationship with clients.
4) The development team should be well-informed and authorized to consider the possible adjustments and enhancements emerging during the development process.
Agile methods are designed to produce the first delivery in weeks, to achieve and early win and rapid feedback. These methods invent simple answers so that change can be less. These also improve design issues and quality as they are based on iteratively incremental method.
What makes a method an Agile?
When the process is :
a) Incremental: Small releases with rapid iterations
b) Cooperative: Customer and developer relationships
c) Straight: The method which is easy to learn and modify with documentation
d) Adaptive: Able to embrace changes instantly
Different Agile Software Development methods
1) Extreme programming
3) Feature driven development
The life cycle of Extreme programming consists of five phases
c) iteration on releases
Extreme programming is a light weight software methodology for a small to medium sized teams developing software in the rapidly changing requirements situation. XP matches the behavior of successful programmers in the wild
Ø Evolutionary delivery
Ø Incremental planning
Ø Less overhead
Ø Embracing change: change can come at any time. Model should be ready to take it.
Ø Rapid feedback: Time between action and feedback is less
Ø Assume simplicity : Initially assuming simplicity of any task and then proceeding according to the solution
Ø Incremental change
Ø Quality work
The term ‘SCRUM’ originally derives from a strategy in the game of rugby where it denotes “ getting an out of play ball back into the game” with teamwork.
Scrum concentrates on how the team members should function in order to produce the system flexibly in a constantly changing environment.
Scrum is extremely simple model ,used by different software companies from long time, which works with existing engineering practices and is scalable and work with common sense which is to say it is very easy.
Scrum process includes three phases
Pre-game phase includes two sub-phases
Planning and Architecture design
Planning includes the development of the required system. A Backlog list is created, which contains all the requirements that are known at that moment. In every iteration the Back log list is updated by scrum team to gain commitment for the next iteration.
Architecture phase : In this phase an abstract view of the model is designed by viewing Backlog list.
The Development phase: This phase takes care of the different variable like time frame, quality, requirements, recourses, technologies and tools. The system is developed in Sprints. Sprints are the iterative cycles where functionality is developed or enhanced to produce new increments. Each Sprint includes the traditional phases of software engineering
4) Evolution and delivery
The Post-game phase close to release.
Ø Roles in Scrum
Ø SCRUM master
Ø Product owner
Ø Scrum Team
Product Backlog defines that is needed in the final product based on current know-how.
Effort estimation is the iterative process which is concentrated on Backlog list
Sprint: It is the procedure of adapting to the changing environmental variables.
Feature Driven Development
FDD is agile approach for software development systems. It provides enough structure for large items, emphasis on quality and working software, delivers frequent , tangible results.
Five phases of FDD
Ø Develop a overall model
Ø Build a features list
Ø Plan by feature
Ø Design by feature
Ø Build by feature
Dynamic systems development method
Dynamic systems development method is the framework of controls for the software development. While developing DSDM systems designers are interested in “ edge case” rather than a mere project “ingredient”.
The principals involved in DSDM are
Ø Active user involvement is imperative.
Ø Teams must be empowered to make decisions
Ø Focus on frequent delivery
Ø Fitness for deliverable is criterion for accepted deliverables
Ø Iterative and incremental delivery is mandatory
Ø All changes during development must be reversible
Ø Requirements must be baselined at high-level
Ø Testing is integrated throughout the lifecycle
Ø Collaboration and co-operative approach
As we came to know that traditional software development approaches are more mechanistic which concentrate more on Processes, tools, contracts and plans. In contrast to traditional methods, agile methods keep emphasis on interaction, working software, embracing change at any moment of the project, customer relationships.
The method can be agile if it is:
“Agile view is more people centric rather than plan-centric.” Agile methods are not defined by a small set of principles, practices and techniques. It creates a strategic capability which has capability of responding to change, capability to balance the structure and flexibility, capability of innovation and creations through development team and uncertainty.
We have also discussed about different Agile Software development models such as
Ø XP (Extreme programming)
Ø FDD (Feature driven development)
Ø DSDM (Dynamic systems development method)