It’s interesting to note how thinking about building systems has changed in the ten years since Design Patterns was published. Bill Venners quotes the GOF book as saying
The key to maximizing reuse lies in anticipating new requirements and changes to existing requirements, and in designing your systems so they can evolve accordingly. To design a system so that it?s robust to such changes, you must consider how the system might need to change over its lifetime. A design that doesn?t take change into account risks major design in the future.
This is certainly something I was taught when I first started off as a developer, but I think now, it?s becoming more and more clear that speculation carries a lot of risk and can be more harmful than helpful. I learned that the hard way, as clients are a fickle lot, and you can guess what they?ll ask for next as easily as you can guess the next super lotto numbers.
Erich?s approach to building an extensibility model with Eclipse reflects how I try to approach projects I work on. In essence, experience a little pain (be it duplication, etc…) before refactoring with a pattern.
I eagerly anticipate part 3 of the interview. Be sure to also read Part 1 of the interview.