/// <summary>
/// Get all options of the type <typeparamref name="TOption"/> which have been set for the service type <paramref name="serviceType"/>
/// or any of its derivatives. Globally-defined options will also be included in the results unless the <see cref="EnableGlobalOptions"/>
/// option has been set to <c>false</c> on the <paramref name="targets"/> target container.
/// </summary>
/// <typeparam name="TOption">The type of option to be retrieved</typeparam>
/// <param name="targets">Required. The target container from which the options are to be read.</param>
/// <param name="serviceType">Required. The service type for which options are to be retrieved.</param>
/// <returns>An enumerable of the type <typeparamref name="TOption"/> containing zero or more options that have been
/// set.</returns>
public static IEnumerable <TOption> GetOptions <TOption>(this ITargetContainer targets, Type serviceType)
where TOption : class
{
if (targets == null)
{
throw new ArgumentNullException(nameof(targets));
}
if (serviceType == null)
{
throw new ArgumentNullException(nameof(serviceType));
}
// global fallback in this instance causes all options - service-specific or not - to be included
// in the enumerable.
bool useGlobalFallback = GetOption(targets, EnableGlobalOptions.Default);
var optionContainers = targets.FetchAllDirect(typeof(IOptionContainer <,>)
.MakeGenericType(serviceType, typeof(TOption))).Cast <IOptionContainer <TOption> >();
if (useGlobalFallback)
{
optionContainers = optionContainers.Concat(targets.FetchAllDirect <IOptionContainer <TOption> >());
}
return(optionContainers.Select(o => o.Option));
}
/// <summary>
/// Gets all globally-defined options of the type <typeparamref name="TOption"/> from the <paramref name="targets"/> target container,
/// returning an empty enumerable if none have been set.
/// </summary>
/// <typeparam name="TOption">The type of option to retrieve</typeparam>
/// <param name="targets">Required. The target container from which the options are to be read.</param>
/// <returns>An enumerable of the type <typeparamref name="TOption"/> containing zero or more options that have been
/// set.</returns>
public static IEnumerable <TOption> GetOptions <TOption>(this ITargetContainer targets)
where TOption : class
{
if (targets == null)
{
throw new ArgumentNullException(nameof(targets));
}
return(targets.FetchAllDirect <IOptionContainer <TOption> >().Select(o => o.Option));
}