Tuesday, 29 July 2014

I Need to Stop Misusing Namespaces

At the recent NSBCon one interesting question that came about was how to structure a project. The panel consisting of various speakers had no answer, after all this is dependant upon the project in question. Therefore there is no right or wrong answer.

However one point they were in unison about was splitting the domain and technical implementation of a project apart by the correct use of in namespaces.

This is not the first time I've come across this, but I find myself breaking this principle on a regular basis. For example a typical project I work on looks like the following.

Problems

  • The namespace reflects a technical implementation detail, and not the problem domain.
  • Using Foo as an example, here the namespace is duplicated within the name of the types, which in turn defeats the point of namespaces.
  • Another issue is that the types can be much longer than they need to be, which is often a criticism of enterprise software development, when the names of objects roll off the screen because they contain so many patterns or conventions.

Solution

Use namespaces for related domain responsibilities. In turn, group together the objects and types that are used together.

An example of a better solution therefore would be:

Benefits
  • Things that change at the same rate, would live logically next to things that also need changes. In other words if I update the FooViewModel, chances are I'll need to update views or controllers.
  • Less typing if you don't suffer a namespace clash!
  • You can still prefix the namespace where required, e.g. Foo.Controller if you have a clash or prefer the readability.
  • Shorter type names!

While this is the ideal way of structuring our applications it's not always possible. Some coding conventions actually encourage the first example, and depending on the configurability of certain frameworks this may prove difficult. That aside, I'll be making a strong push towards structuring my projects correctly going forwards.

2 comments:

  1. Great observation and well said! I too used to structure my projects in a utility sense whereas the best way to do it is to use the application's semantics

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    Replies
    1. Thanks - a year after I wrote this I'm still very conscious of using namespaces in a more suitable manner but it can be hard, especially with legacy code/frameworks.

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