Tuesday, 31 March 2015

Anatomy of a class.

Do you ever view a class and get filled with a sense of dread?  I did today, so I thought a good old-fashioned rant was in order.

I opened up a class today and was greeted with this.   First off, don't worry, I made the Wibble up.  Secondly, if wibble was the first thing you noticed we're probably in trouble.

    public sealed class MultiWibbledEntitiesDataPresenterFactory<TDetectionContext, TWibbledEntity, TProvider> : BasicFactory<Unit, IDataPresenter<MultiWibbledEntitiesContext<TDetectionContext, TWibbledEntity>>>
        where TWibbledEntity : WibbledEntity
        where TProvider : IProvider<TWibbledEntity>
        private readonly IUtcDateTimeProvider m_UtcDateTimeProvider;
        private readonly ILocalDateTimeProvider m_LocalDateTimeProvider;
        private readonly IWibbledEntityDetector<TDetectionContext> m_WibbledEntityDetector;
        private readonly IFactory<TWibbledEntity, TProvider> m_ProviderFactory;
        private readonly IFactory<TWibbledEntity, IDataPresenter<SingleWibbledEntityContext<TWibbledEntity, TProvider>>> m_RawWibbledEntityDataPresenterFactory;
        private readonly Func<IUtcDateTimeProvider, string, IStatusLogger> m_StatusLoggerBuilder;

        public MultiWibbledEntitiesDataPresenterFactory(
            IUtcDateTimeProvider utcDateTimeProvider,
            ILocalDateTimeProvider localDateTimeProvider,
            IWibbledEntityDetector<TDetectionContext> wibbledEntityDetector,
            IFactory<TWibbledEntity, TProvider> providerFactory,
            IFactory<TWibbledEntity, IDataPresenter<SingleWibbledEntityContext<TWibbledEntity, TProvider>>> rawWibbledEntityDataPresenterFactory,
            Func<IUtcDateTimeProvider, string, IStatusLogger> statusLoggerBuilder
            m_UtcDateTimeProvider = utcDateTimeProvider;
            m_LocalDateTimeProvider = localDateTimeProvider;
            m_WibbledEntityDetector = wibbledEntityDetector;
            m_ProviderFactory = providerFactory;
            m_RawWibbledEntityDataPresenterFactory = rawWibbledEntityDataPresenterFactory;
            m_StatusLoggerBuilder = statusLoggerBuilder;

        protected override IDataPresenter<MultiWibbledEntitiesContext<TDetectionContext, TWibbledEntity>> ConstructItem(Unit key)
            return new MultiWibbledEntitiesDataPresenter<TDetectionContext, TWibbledEntity, TProvider>(

OK, you've read through that.  You've probably died a little inside. What did you learn?  Well, this is a MultiWibbledEntitiesDataPresentorFactory.

What the actual fuck?

A multi wibbled entities data presenter factory.

Spacing it out doesn't help much either.  It's a factory that makes data presenters for multi wibbled things.  OK, that starts to make some sense.  I guess I'd use this class if ever I needed to make a multi-wibbled-entities-data-presenter-factory.

Let's say that's the case. How do I construct one of these factory things?  I need a couple of time providers (UTC and local time, just in case), a detector (no idea what that is), two more factories and a function called "statusLoggerBuilder".  And this is just to create an object (albeit a rather complicated multi-wibbled data presenter object).

What can you do with the class?  Not a lot, there aren't any public methods other than the constructor, and that's pretty boring.  So, in order to make any progress, you'll have to explore a few more classes.  You'll need to visit the "BasicFactory".  You'll need to look at Unit, IDataPresenter and a few more parameterized classes.  In order to work out what this does, I've got to read all these files.

What's with all the generics?  Does this tell me the original developer was a template meta-programming C++ person?  Why all the complexity?

How many files do I need to open in order to understand this class?

What problem is this class solving?  The code doesn't tell me this, there aren't any comments and there aren't any tests.  The only way for me to understand this code is to navigate all the code's friends and work out what each of them do.

But on the plus side, I can create one and test it, so it must be good right?