  | 1 of 47
 |   |
| | 1 of 47
| |
Agile methods are a modern approach to incremental development.
They emphasze:
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 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.
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) 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.
Each successive version of the product
Contrast this with a strategy of delivering successive, complete subsystems that will not be revisited.
When can you start using the house?
A user story is a simple description of desired functionality, often written as a single sentence on an ordinary index card.
Over time, user stories are modified by
In an incremental construction process, small sets of stories are chosen for an upcoming increment as the target for the next round of construction.
As a calendar owner, I want to view my schedule for the coming week.
As a visitor, I want to see when a calendar owner has free time in their schedule.
As a calendar owner, I want to receive email notication when someone accepts a proposed appointment.
As a systems administrator, I want to back up all calendars so that the data is safeguarded.
These illustrate some common patterns:
{role}, I want {goal/desire}”{role}, I want {goal/desire} so that {benefit}”…despite the focus on functionality and non-functional characteristics.
Commonly, stories are split into tasks that are shown in a common swimlane.
Teams are supposed to keep themselves up-to-date.
Teams typically try for 4-10 stories per iteration
Select stories to implement in current implementation
Often organized onto a task board
Rate at which functionality (user stories) completed per iteration.
Most agile approaches define a fixed number of days per iteration
Add up the effort estimates of all stories completed during an iteration. This is the team’s current velocity.
Contains stories to be completed in current iteration
Combines story cards and task notes
Task notes organized in columns
Setting a work pace that can be sustained indefinitely
Once a pace has been established, teams can measure velocity
(Kent Beck)
Each code unit
Test-Driven Development goes beyond the commonly sited “test first, code later” rule
The four steps above are repeated, adding new, tested functionality each time.
Design is on-going
Principles include
“You Ain’t Gonna Need It” - argument against early design of elaborate components for future use: “We going to need X eventually. We might was well design it now.” “YAGNI”
Design should be emergent
The most popular agile approach, characterized by
Scrum in Context
As the name suggests, Scrum
Transparency
Inspection
Adaptation
Product owner
Product owner
Product owner
Product owner
Scrum master
Product owner
Scrum master
Product owner
Scrum master
Product owner
Scrum master
Product owner
Scrum master
Product owner
Scrum master
Product owner
Scrum master
Development team
Product owner
Scrum master
Development team
Product owner
Scrum master
Development team
Product owner
Scrum master
Development team
Held at beginning of sprint:
15-minute daily meeting
Each development team member explains
Product owner
Development Team
Entire team
Team inspects its own performance
A burndown chart shows amount of work remaining in the sprint backlog
An extension to Scrum for larger projects:
| | 1 of 47
| |