A class that performs both computations and data logging* seems to have at least two responsibilities. Given a system for which the specifications require heavy data logging, what kind of design patterns or architectural patterns can be used to avoid bloating all the classes with logging calls every time they compute something?
The decorator pattern be used (e.g. Interpolator decorated to LoggingInterpolator), but it seems that would result in a situation hardly more desirable in which almost every major class would need to be decorated with logging.
*Note: When I wrote this, I was working in a context in which it was called logging, but it was actually writing to a database. I’m not particularly referring issuing debug or error messages in a log4net log or the like.
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My first thought is to treat the computational parts as a model, and the logging parts as a view. You could then manage the work flow activities of each using a controller or presenter pattern. Substitute other fancy names for each part if you wish, but I see three parts.
So, the controller would initiate the computation, retrieve the result, and relay that to the logger. The computation and logging parts stay ignorant of each other, and the high level logic of your main job is expressed in one place.
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