Spiking with spikes: what is a spike?

16 Mar

Posted by toni as OOD, TWBlog, Agile

What is a spike?
That question came out at the second Hong Kong Agile meeting, last Wednesday.
I was surprised, a spike was something in my base knowledge, something obvious.
I think I’ve learned first the world spike in a programming context rather than spike in any other context.
Probably is not so obvious and makes sense to blog about it.

knowledge spikes

My first spike was quite few years ago, on my first medium size Enterprise project.
The aim of the spikes was to understand a current system, from the database layer to the UI.
It was pain, I still remember it. It took me almost a week, asking help many times, it wasn’t an XP project.
At the end of the exercise I was able to understand very well the system, and able to contribute well on the project.
The code produced was checked in. To provide context, knowledge for future joiners in the project. Code that should not run in production.

Basically it was a main class, instantiating all what you need to start up the full system.
I’ve to say that the codebase was definitely well designed, otherwise doing such an exercise cold be very very diffult.

spikes checked-in?

Conrad, while giving his presentation with Tom on Agile techniques stated that there should be no check in of the code, since that code should never go on production.
I disagree on most cases, there’s always a value on the spikes.

The only spikes I would not check in are my personal trials to understand what’s going on, crappy code that I would not show us to anybody, so ugly that it doesn’t deserve the honor to go on the code repository: One shot spikes.

design sets spikes

On my last project with Pat we tried different design sets (also including technology decisions) for a big problem of redesign/refactor we had.
Also in that case we put the code under version control. Why? For future joiners for instance, these was what we tried, the solution that won it’s on the trunk, the failures on a sperate trunk folder, spikes can be a good name right?
I’ll take the same approach also starting a new project. Let’s pretend I’ve to start a new java project, an app with a database layer. You can spike the database access with Hibernate, with Ibatis, with EJBS, etc…
It will help you in estimating future stories, in the understanding on how much the chosen solution is testable.

estimations?

A spike should always be estimated, a fixed amount of time can be allocated during an estimation session.
A spike should always achieve a final goal.

If a spike screw completely the estimation throw it away, something is wrong, probably the design, the technology you’re trying to use is too complex to play with it, don’t insist on.
Throw away but check it in, even if not working, on the spikes trunk! I can’t imagine any better documentation for new joiner to justify, to explain, that’s why we didn’t use EJBs, look at that!
Shall I write tests doing a spike? Why not. If you’re trying to find a design I can’t imagine anything better that some old good TDD, if you’re trying to understand the system you can write a main if you’re not familiar with tests or just some tests. A spike can be made of tests.

more on the web…

Take a look also on the definitions on C2.com.

XP.org has his definition as well.

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Java Essentials

16 Mar

Posted by toni as OOD, TWBlog, DDD, That's Cool!, Java

My friend Bruno kicked off, silently few weeks ago the Java Essential project.

What is Java Essential?

It’s an open, collaborative book, written in Italian about Java and not only.
It will cover topics like TDD, Object Oriented Design and Domain Driven Design, and all the most current/good/trendy frameworks.
It will be written in Italian, for the Italian Java (not only Java really…) community, written by the communities, in fact various good guys from various different Java User Groups and Organizations will write the content.

I’ve been asked to write the chapter about Domain Driven and since I’m not a good writer I’ve asked to Floyd Marinescu if I can translate his nice Domain Driven Design Quickly, and he agreed.

Depending on how much it will take and on how much time I’ll be able to allocate on this project I’ll translate partially the book for Java Essential or the full book, linking it then on InfoQ.
If there’s one thing that I care about is to spread around the world what we do and how we do it, last year I had in total four speeches in Rome, Turin, Varese and Bologna, since I’m a bit far from Europe now, that’s the best way to continue in that direction

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Qi4j: an implementation of Composite Oriented Programming

24 Feb

Posted by toni as TWBlog, ThoughtWorks, That's Cool!, Java

Many thanks to Dan that pointed out on our internal ML to Qi4J.
Quoting from the home page:

Principles
- Composite Oriented Programming builds on some principles that are not addressed by Object Oriented Programming at all.
- Behavior depends on Context
- Decoupling is a virtue
- Business Rules matters more.
- Classes are dead, long live interfaces.

Are you already worried that they’re using xml to do this?

Qi4j is trying to address the flaws of OOP and introduce Composite Oriented Programming to the world, without introducing new programming languages, or awkward constructs. Heck, we don’t even use any XML.

Definitely interesting.

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bye bye London

19 Feb

Posted by toni as TWBlog, ThoughtWorks, General Stuff

Well, with a flight and an hotel booking in my bag I think it’s enough official, I’m moving to China, Hong Kong more precisely (there’s Beijing planned in 3 months but that’s another story).

Playing for a while again (after a good year spent with (alt).Net) with old good Java Code and financial sfuff like Fix, Securities and Fidessa. I’ve the feeling that’s gonna be fun and I’ll meet few fellow Twers there aka AgileHongKong Crowd

Going East has been an objective in my life since I’ve read a Fortune Teller Told me, will I ever come back to Europe? We’ll see.

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