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Beck and Andres on Extreme Programming
narramissic writes "In recent years, Extreme Programming (XP) has come of age. Its principles of transparency, trust and accountability represent a change of context that is good not only for software development but for everyone involved in the process. In this interview, Kent Beck and Cynthia Andres, co-authors of 'Extreme Programming Explained: Embrace Change,' discuss how XP makes improvement possible."
But when you put two programmers with equal authority, you have one thinking about the bigger picture and the other reviewing his mind flow. At the same time the later is writing down the ideas in code, with the first one reviewing his code as he types.
Where have you been the last 20 years? The stereotypical programmer, hacking his piece of kernel over night is very endangered species, and rightly so. Like any kind of engineering, software engineering needs as much face to face collaboration as possible.
Kent Beck hits the proverbial nail on the head with this zinger (which I'm sure is certain to stir up quite a few):
... I think programmers are, or at least can be, adults and can and should, for the good of development and themselves, act that way."
"It's not all about programming. It's not all about programmers. Programmers aren't somehow special and to be protected and coddled. I used to say often that programmers were children. They liked not to be yelled at and to have more toys
The above quote sums up almost every problem that I have seen over the past 10 years with the various development shops I've been a part of.
Pair programming can be seen as a kind of code review, but with the reviewer in equal position with the programmer. Traditional code reviews tend to be frustrating for the programmers, because the reviewers are in position of authority.
I've never seen one of those. Every code review I've participated in has been a collaborative effort between peers. If you treat a code review as a cooperative effort between programmers, it doesn't have to be frustrating.
Like any kind of engineering, software engineering needs as much face to face collaboration as possible.
To a point. But real engineering requires planning and clear interface definitions, and XP -- almost to the point of being pathological -- attempts to avoid planning as much as possible by subsitituting endless chatter and tremendous time wasting repeatedly reimplementing what could have been done right the first time. (And yes, I know some things always have to be reimplemented, but just because mistakes are inevitable doesn't mean they have to be encouraged.)
Software development has an unfortunate tendency towards fanatical adherence to the latest silver bullet. Usually, this involves an implementation language backed by a marketing push; XP seems to be the first programming fad built entirely on book publishing. But then, no implementation language ever actively encouraged the kind of passive-aggressive personality that thrives on XP.
Proud member of the Weirdo-American community.
It's an attempt to achieve a greater level of quality through process/practices, which is as close as "software engineering" has gotten to real engineering so far. Arguably, though, "software engineering" isn't real engineering until you use formal methods to ensure the correctness of your design and implementation.
I view XP as a methodology to solve a major problem I've seen in software - communication.
/before/ the code is written, the latter written by the customer(!)). We continually run them using a Continuous Integration server which monitors the code repository and checks out the latest version, notifying the team of any conflicts.
/not/ to be "XP", it's to deliver value to the customer. And if your current practices are doing that, then that's what is important.
Why do we build software? It's to provide value for our customer, whether that customer be a marketing department, a gamer, or ourselves. And if we don't keep in touch with what it is that they want (recognizing that people generally don't know what they want until they see it), we probably won't provide the value we could.
To that end, XP encourages constant communication by using frequent releases of the stories (read: features) the customer thinks are most valuable. The customer gets a working version every week, or month, or 2 months, or whatever cycle seems to work for the team.
From the development side, XP encourages the code to always be potentially shippable by having a suite of Unit and Acceptance tests (the former written by the developer
It also encourages things like Collective Ownership, where, in theory, any developer can sit down and work on any part of the system. This is achieved partly through the unit test suite, and partly through pair programming with frequent swapping (we swap pairs generally twice a day, in the morning and at lunch, but some teams do more, and some do less).
But, regardless of all the practices (and there's more than I'm listing above), the end goal is
As far as TDD, I have a series I recently did which shows how TDD works here (part 1) and here (part 2).
Random Musings
First a disclaimer: I worked on an ADP project that involved Intelliware - an XP shop to build a mutual fund prospectus preprinting system (system that collected information from different mutual fund vendors, and used customer information to decide what and when to print and to mail to that customer.) This was a second iteration of the project. The first iteration had to be scrapped, because the same vendor provided a solution that did not scale to the task, when major Canadian banks came online.
My impression from the entire excercise, (which included daily standup meetings, story cards, paired programming, unit testing, end of the day documentation.) The process became very very wasteful. I personally saw that putting 2 contractor programmers, each at 90/hr at one workstation does generate dialog between the programmer, where both have to generally agree on the approach to any given problem but I did not see any performance improvement achieved by this approach over havin one 90/hr contractor doing the same thing. Since the requirements of the system were still being 'refined' and since there still were deadlines to achieve, the pair had to produce as much code as possible in a very short time period and various bugs still slipped through the process (most of which admittedly were caught by the unit testing, but unit testing.)
The daily standup meetings were mandatory of-course even though most people loathed those. There still were 'overal architects' on the process, and due to the politics of this specific vendor they forced a custom server solution upon the customer (even amid my vivid objections. I was trying to get the vendor to use existing server and framework solutions, unfortunately my voice was not heard, there was no will to prevent the imminent demise of the project by concentrating on the problem at hand and not getting ourselves into a proprietary application server territory.)
Basically the project was not delivered on time (and as I at the time predicted) went over the original time estimates by about a year. I was forced to leave 3 months into the project because I became to frank with the department director. 3 months after I left, Intelliware was forced out the door as well. The project was partially delivered within the time that I estimated, the department director had to leave the department as well.
I do not get any warm and fuzzy feelings about anyone promoting XP, I right away start looking for ulterior motivations. My personal feeling is that people who do not want to carry any responsibility for the project, for the code, for the requirements welcome XP (or can be easily swayed to accept that methodology.)
In XP noone is really personally responsible for anything, and that attracts people who want to have it easy. Documentation is shunned upon, any forward thinking is met with contempt. Any questioning of the process/methodology is considered a heretic. Sweat shop mentality dominates XP, and it is not surprising, considering that it takes 2x as many people to deliver the same solution for 2x the money. Obviously there is a drive for those, who are actually producing code to work as fast as possible without any room for thought.
I did however find that unit testing is a very good approach to testing and that wiki style documentation is excellent if used properly.
You can't handle the truth.