If you’ve ever been to a vineyard, you’ve probably seen that they plant rose bushes at the end of each row of grape vines. These rose bushes indicate if there is going to be a problem with the grape vines because the roses are generally weaker than the grape vines, yet have almost the same genetic make-up. The roses will die first if there is a pH-imbalance, insufficient water, too much water, too much sun, or other issues with the environment. The viticulturalists can then react before the …

I like Martin Fowler’s write up on Designed Inheritance, but I’m not so sure I agree with his implied suggestion that you cannot have designed inheritance and provide an enabling design.
If I have a component that is being called by other code, and that component is implemented as an abstract class that only allows subclasses to implement abstract methods (all concrete methods are final), then I cannot override the behavior of the parent class. This is designed inheritance because people can only subclass it in the way that I’ve …

I teach TDD courses, and one of the questions that inevitably pops up is whether you should refactor your tests. When it comes to eliminating duplication in tests, my threshold is very high. By that, I mean that the most important thing to me is readability. I want to read a test like a mini story: I set this up, I execute this, I verify that.
One of the biggest annoyances I encounter with experienced TDDers is when they decompose tests to the point where you can’t see what the …

I’ve was going to write something today and I wanted to use the idiom “from a 20,000 foot view”…

In July of 2005, I received an e-mail from an editor at Manning Publications Co. regarding some articles that I had written about JBoss. They liked my writing style and wanted to see if I was interested in writing a book on JBoss. I pitched a table of contents for a book that would be in their “In Action” series and they accepted it. Now, nearly two years later I, along with my co-author Peter Johnson, are approaching the production stage for our book, JBoss in Action.
Between the two of …