Namespace Rule of Thumb

Question

Is there a general rule of thumb as to how many classes, interfaces etc should go in to a given name space before the items should be further classfied in to a new name spac

Answer 1

I would argue that the namespace hierarchy should only be gouverned by considerations of design and the hierarchy of the model/API.

If one namespace sports huge number of unrelated classes, rethink your design.

Contrary to what Andrew said, I would not worry about namespaces containing few classes – although it's of course true that the hierarchy should only be as fine-grained as needed to express the design.

On the other hand, I find it completely reasonable for a namespace to contain only one highly special class, or perhaps just a very small set of types, of which one encodes the task and the others provide an API (exceptions, enums for arguments …).

As an example, take System.Text.RegularExpressions (in .NET). Granted, slightly more than one class, but only just.