Improve Factories

[MehdiK]

We have a few factories in the codebase in charge of returning an instance of a class based on the ambient culture. Here is an example of a factory:

    private static readonly IDictionary<string, Func<IFormatter>> FormatterFactories =
        new Dictionary<string, Func<IFormatter>>(StringComparer.OrdinalIgnoreCase)
    {
        { "ro", () => new RomanianFormatter() },
        { "ru", () => new RussianFormatter() },
        { "ar", () => new ArabicFormatter() },
        { "he", () => new HebrewFormatter() },
        { "sk", () => new CzechSlovakPolishFormatter() },
        { "cs", () => new CzechSlovakPolishFormatter() },
        { "pl", () => new CzechSlovakPolishFormatter() }
    };

    private static IDateTimeHumanizeStrategy _dateTimeHumanizeStrategy = new DefaultDateTimeHumanizeStrategy();

    public static IFormatter Formatter
    {
        get
        {
            Func<IFormatter> formatterFactory;
            if (FormatterFactories.TryGetValue(CultureInfo.CurrentUICulture.TwoLetterISOLanguageName, out formatterFactory))
                return formatterFactory();

            return new DefaultFormatter();
        }
    }

Basically every time we call Formatter, which is quite frequent, we're creating a new instance for the Formatter/NumberToWordsConverter/Ordinalizer, and this is quite bad.

We need to change the factory to return a lazy instance instead so it's created on the first call and available from then on.

[hazzik]

But creation of these classes is really cheap.

UPD it seems that creation of the stateless class is much faster than using Lazy<>

[MehdiK]

The creation will be cheap; but using Humanizer on a website with many calls to localised methods will create so many objects in memory. These will be eventually GCed; but do we really need 1000s of these classes in memory?

[MehdiK]

Fixed in #243