This course delves into a variety of processes to structure software development. It also covers the foundations of core Agile practices, such as Extreme Programming and Scrum. Upon successful completion of this course, you will be able to: - Distinguish between different process models for organizing software production. - Gauge the applicability of process models for a software development project. - Apply the fundamentals of Agile software development and management practices.
2.3.2B: Extreme Programming
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來自 University of Alberta 的課程
Software Processes and Agile Practices
2080 個評分
從本節課中
Module 3: Agile Practices
Do you want to help developers reach their full potential? Do you want to impress clients by delivering a great product on-schedule and on-budget? Then this module is the place for you! In this module, you will learn some Agile methodologies that are practiced in the industry today. This module will cover the Scrum and Extreme Programming methodologies. The practices in these methodologies are some of the most popular practices in the industry today. They provide practices that will help to maintain organized and effective development. These methodologies will help you to know the exact state of your product and deliver successfully!
與講師見面
Kenny WongAssociate Professor
Computing Science, Faculty of Science
[MUSIC]
Danielle is the product manager working with a five-person development
team to create a payroll application that allows small business owners to pay their
employees.
After delivering the prototype,
the client sends out a nasty email to the development team saying that they
found a bug in the application that calculates the wages incorrectly.
The client is very upset.
This bug would cost the business owners a great deal of money, and
employees would end up getting more money than they have earned.
Timmy and Maria were the programmers who co-wrote the unit test for this feature.
Steven and Maria were the programmers who pair programmed the source code.
Danielle, the product manager, conducted the acceptance test for
the product before the release.
Who is to blame for this error?
Choose all that apply.
A, Danielle, B, Timmy, C, Maria, D, Steven,
and/or E, the other two developers on the team.
A practice of extreme programming is collective ownership.
This means that all members of the team are responsible for errors that occur.
Therefore, everyone is at fault.
That means A, B, C, D, and E are the correct answers.
Had the client been very satisfied with the product,
the entire team would get credit for the success.
I said earlier that extreme programming is traditionally described
by 12 basic practices.
However, depending on what resource you are looking at,
they could be expressed differently.
Don Wells is the author of the first version of Extreme Programming Rules.
Instead of the 12 practices, he lays out 29 extreme programming rules.
Many of these rules overlap with the 12 we just went over, or
they combine many practices from Scrum.
There are however a few management practices that do not fit into
either of those categories, that are interesting to note.
The first practice is give a team a dedicated, open work space.
Think about the work spaces that you have previously worked in.
Do you think they enhanced your productivity and teamwork?
XP suggests that the work space have multiple computers that belong to no one.
They should be located in the middle of the room and not along the walls.
This encourages the development team to work together.
There should also be a meeting table with white boards where your teams can
collaborate and brainstorm.
The next practice is move people around.
This encourages communication and flexible work relationships.
This means that everyone knows how to develop and
operate all parts of the product.
Think about how detrimental it will be to your project
if there is only one person who knows how a feature works.
What happens when they leave?
You will be left with a void in your development.
An alternative option to moving people around would be to
heavily document features.
However, this is not the agile way.
You wouldn't have a professional soccer team without a backup goalie.
Likewise, the success of your project should not depend on one person.
In sports or development,
the most useful team members are the ones who are good at multiple skills.
The final management practice is about changing XP itself.
That is, fix XP when it breaks.
You may have noticed that it says when it breaks, and not if it breaks.
That's because it is going to break.
It's not going to run smoothly throughout the entire life cycle of your product.
Not all of the practices of XP will work well with your team.
When something doesn't work, change it.
You're going to want to have your team follow the rules until they break.
Frequent project retrospective meetings are a great way to determine
what's working and what's not.
You have been hired by a company that say they have tried to
implement the extreme programming methodology exactly.
You walk into the workplace and see a maze of cubicles.
As you walk around the work space and peek into cubicles,
you see pairs of programmers working together.
You pop into a cubicle and ask the developers where they can find the client.
One developer hands you a business card that has the client's phone number on it.
He says you can leave a message there and the client will get back to you.
You go into the next cubicle and
ask the two programmers working there when the next release is due.
They tell you that the releases are due every second Friday.
They have a release coming up this Friday.
You ask these programmers what they are working on.
They explain that they are the database team, and
that they exclusively work on maintaining and building the database.
You realize that there are many areas of extreme programming that they are not
following properly.
What are some areas of development that you are going to need to change in order
to have extreme programming running precisely in this office?
A, the workspace, B, pair programming, C, client availability,
D, small, frequent releases and/or E, developer versatility.
An Extreme Programming workspace environment is open and
encourages collaboration.
A maze of cubicles does not align with that practice.
The client should also be available at all times.
A hard-to-reach client does not encourage effective communication.
Finally, developers should move around and not specialize in a feature.
Having two developers exclusively working on the database does not comply with
extreme programming.
Therefore A, C, and E are the correct answers.
This company is not completely off base.
They do engage in pair programming and
deliver small, frequent releases, which are good extreme programming practices.
Now that you are well versed in the rules of XP,
let's talk about some of the downfalls of XP.
One downfall of XP is the need for the all or nothing approach.
If you are adopting XP for your development team,
you are encouraged to adopt all the rules of XP to get the full benefits.
Yes, I did mention that you can change aspects of XP that are not working.
But at what point is it still considered extreme programming?
What happens when half the practices don't work for your team?
The individual practices do not have as much value as the overall methodology.
But sometimes, implementing all of the practices is just not practical or
possible.
Another weakness of XP is that it is designed for small development teams.
What happens when you have over twenty people on your development team?
You are going to run into many issues with collective ownership and integration.
There is also a lack of upfront planning with XP.
Compared to other methodologies, XP does not encourage real up front software
architecture planning, and this could lead to a lot of reworking in the future.
And what about pair programming?
Sure it has a lot of benefits, but
it has not been as widely adopted as other practices.
I can guarantee it will not work with all teams.
Personality conflicts will play a huge factor.
And finally, it's difficult to arrange an on-site client.
It's uncommon that a client be made available for the time required by XP.
It's often unrealistic to expect the client to be there every time an issue or
question arises.
In an ideal world, yeah, it would be awesome for a client to always be there.
But this is real software development, where things are often far from ideal.
Extreme programming outlines many great practices for software development.
But the process also has many downfalls.
As a product manager, you're going to need to find practices that work for your team.
You'll need to experiment, maybe XP will work perfectly for you, and
maybe it won't.
That's why you must examine many methodologies, so
that you can discover the right one for your team.
You need to gather data to support which practices can work for you.
On that note,
in the next lesson you will get to move onto another methodology called Scrum.
