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by Jared Richardson.
Original Post: Coding to an Interface by Erich Gamma
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The web site was created after the launch of the book "Ship It!" and discusses issues from Continuous Integration to web hosting providers.
I saw two interviews with Erich Gamma today at Artima.com, but the second interview caught my eye. (Okay, they both caught my eye, but I blogged on the first article at work, so I'm trying to do something different!)
The summary reads:
In this interview, Erich Gamma, co-author of the landmark book, Design Patterns, talks with Bill Venners about two design principles: program to an interface, not an implementation, and favor object composition over class inheritance.
What caught my attention? Coding to an interface is a major part of Tracer Bullet Development, which is a major part of Ship It.
One of the big ways we've used Tracer Bullet Development is by defining the interfaces (or APIs) between major parts of your system. That's the design by contract between the developers in each section.
As long as the interface doesn't change, the developers in a given area can go crazy with retooling or refactoring. The developers above and below shouldn't know that anything changed.
These interfaces also give you a great place to code your automated test suites. By testing at the API level you (1) ensure the entire product area still works properly and (2) validate that the code works as intended instead of "working at coded".
There is an entire chapter on Tracer Bullets in Ship It, but this should give you a basic idea... it's nice to see Erich's article and know that we lined up with a smart guy! :)
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