Language Matters

  • Posted By Stuart Halloway on May 21, 2007

My Design Patterns are Code Smells post has been picked up by TheServerSide.com. It is interesting to read through the comments. One side exchange about Test-Driven Development includes this observation:

I think the point of the TDD comment is that TDD forces you to consider using interfaces to reduce coupling between classes.

Yes, near 100% of my data access interfaces have exactly one implementation. But I never create these interfaces because, gosh, I may want to change from Oracle to Some-New-Cool-Database in the future.

This is a terrific example of how implementation languages color your thinking. Notice how easy it is to switch between concept and implementation details:

  • "TDD forces you to consider..." (conceptual)
  • "...using interfaces to..." (language-specific)
  • "...reduce coupling..." (conceptual)
  • "...between classes." (language-specific)
There is nothing wrong with this level-jumping; it is often more concise than speaking at a single level could be. Just make sure that you understand what level you are playing at, and why. Otherwise you might conclude that
  • "If only I had an interface ..." (language-specific)
  • "...then I could mock my data access layer..." (conceptual)
which says more about your platform choice than it does about the problem at hand.

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