ObjectOrientatedNamedServiceProviderDemo

ObjectOrientatedNamedServiceProviderDemo.cs

private static IServiceProvider GetServiceProvider()
{
    var services = new ServiceCollection();
    services.AddSingleton<CentigradeToKelvinMapper>();
    services.AddSingleton<FahrenheitToKelvinMapper>();
    services.AddSingleton<RankineToKelvinMapper>();
    services.AddSingleton<KelvinToKelvinMapper>();

    services.AddSingleton<KelvinConverterMapper>(provider => key =>
    {
        switch ((string.IsNullOrEmpty(key) ? " " : key).ToUpper()[0])
        {
            case 'C':
                return provider.GetRequiredService<CentigradeToKelvinMapper>();

            case 'F':
                return provider.GetRequiredService<FahrenheitToKelvinMapper>();

            case 'R':
                return provider.GetRequiredService<RankineToKelvinMapper>();

            case 'K':
                return provider.GetRequiredService<KelvinToKelvinMapper>();

            default:
                return null;
        }
    });

    services.AddSingleton<TemperatureCalculator>();

    return services.BuildServiceProvider();
}

private class CentigradeToKelvinMapper : IKelvinMapper
{
    public decimal ToKelvins(decimal value) => value + 273.15M;
}

private class FahrenheitToKelvinMapper : IKelvinMapper
{
    public decimal ToKelvins(decimal value) => (value + 459.67M) * 5 / 9;
}

private class RankineToKelvinMapper : IKelvinMapper
{
    public decimal ToKelvins(decimal value) => value * 5 / 9;
}

private class KelvinToKelvinMapper : IKelvinMapper
{
    public decimal ToKelvins(decimal value) => value;
}