Software Quality

Software Reuse Antipatterns

coderIn 2000, Scott Ambler wrote  an excellent article on the organizational aspects of software reuse. He talked specifically about patterns and antipatterns:

“A pattern is a common approach to solving a problem that is proven to
work in practice. Conversely, an antipattern is a common approach to solving a problem that leaves us worse off than when we started.”

Long (2001) built on Ambler’s work and made it more fun. (This is, in my opinion, one of the most interesting and entertaining articles about software reuse in existence. You can get the full text from the ACM if you have an account there.) Long calls antipatterns obvious, but wrong, solutions to recurring problems and characterizes four organizational approaches that don’t support successful software reuse. See if your organization is one of these:

  • Abracadabra Model: A high-level manager is frustrated with a perceived lack of reuse and declares that “reuse will happen”. What Happens: Lots of talk, no action, silo development continues, managers start to panic, then the organization “de-evolves” into the next model.
  • High Noon Model: A high-level manager is REALLY frustrated with a perceived lack of reuse and declares that “reuse will happen”. What Happens: Finger pointing, as everybody has a lot of reasons (many of them very good, and very accurate) about why reuse can’t possibly work. The de-evolution continues.
  • Cost Cutter Model: A high-level manager is REALLY, REALLY frustrated with a perceived lack of reuse and declares that “reuse must happen to cut costs”. What Happens: Software people start to “force” reuse, immediate costs go up, upper management gets nervous, and more finger pointing happens (as everybody finds even more reasons now – including higher cost – for why reuse can’t possibly work.)
  • Used Car Fiasco Model: Software group says “OK, we’ll try reuse.” One group has software it thinks about group can use, so it is made available as-is and with no support. What Happens: There are lots of bugs to fix. Reusers have to fix them because the originators don’t have the time or resources to solve the new group’s problems. The reusers get frustrated and then write the code themselves.

Note that in all models, the expectations and behavior of the managers doesn’t change. In the fourth model, the behavior of the software developers changes. At no point do the expectations of the software developers change – their mission is to do what they need to do to get the software written.

Tomorrow I’ll write about why I think software reuse is difficult. The antipatterns above provide a good foundation for that discussion.


Ambler, S. (2000). Reuse Patterns and Antipatterns. Dr. Dobbs Journal, February 1, 2000.
Long, J. (2001). Software Reuse Antipatterns. ACM SIGSOFT, Software Engineering Notes, 26(3), 68-76.

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