The part that I hate the most about a project of a type that I never done before is the start. The issue is that I produce a design that mostly works, but when new stuff need to be implemented, I often need to explore several approaches before I know what will work for this project, my last post in an example of the approaches I thought about for persisting object graphs.

The thing that really bothers me is that changing those approaches can lead to major changes in the code. This means that there are extended periods of time that I can't even build the code successfully (30 minutes to an hour, at times). This makes me very nervous, but I don't see how I can avoid doing this as I study the various ways to implement this functionality. In this case, the changes involved changing an interface that was common to many classes in the project, so that caused quite a bit of pain until I settle on the correct approach.

I was at the Israel User Group meeting today and talked with Justin who termed this as a "Design Bug". I like this term. The only encouraging part is that after the initial pain I get a stable base to work from. The bad part is that the changes are big enough that I can't really test drive them beyond very big tests (save the object graph and then load it, for example). Those type of tests are more integration oriented than developer oriented. They help me define the big goal, but not how I get there.

I guess that this is why XP has Spiking for unknown functionality. I'm pretty sure that I'm commiting horrendous crime for doing this with code that will go to production, but in this case, I don't have much implemented yet (only some interesting graph output functionality), so I feel that it is safe to do this.

One thing that I noticed happening is that I lose abstraction along the way. For instnace, when I tried XML Serialization, it couldn't handle interfaces, so I changed several interfaces to abstract classes. When I realized that XML Serialization would probably not work, I revert the changes. For now, I'm seeing this as removing premature abstraction on my part, and if I need this functionality later, it wouldn't be a problem.