/// <summary>
/// If the received value is null, <see cref="ValidationException"/>
/// is emitted as an error with the status code 404 (Not Found).
/// Otherwise the given value is emitted.
/// </summary>
/// <typeparam name="TSource">The type of the value.</typeparam>
/// <param name="observable">The parent observable.</param>
/// <param name="errorFactory">The error factory method.</param>
/// <returns>An instance of <see cref="IProviderObservable{TSource}"/>.</returns>
public static IProviderObservable <TSource> NotFoundWhenNull <TSource>(
this IProviderObservable <TSource> observable,
Func <TSource, object> errorFactory = null) =>
observable.InvalidWhen(s => s == null, StatusCodes.Status404NotFound, errorFactory);
/// <summary>
/// If the check returns <c>true</c>, <see cref="ValidationException"/>
/// is emitted as an error with the status code 404 (Not Found).
/// Otherwise the given value is emitted.
/// </summary>
/// <typeparam name="TSource">The type of the value.</typeparam>
/// <param name="observable">The parent observable.</param>
/// <param name="invalidCheck">The invalidCheck function.</param>
/// <param name="errorFactory">The error factory method.</param>
/// <returns>An instance of <see cref="IProviderObservable{TSource}"/>.</returns>
public static IProviderObservable <TSource> NotFoundWhen <TSource>(
this IProviderObservable <TSource> observable,
Func <bool> invalidCheck,
Func <TSource, object> errorFactory = null) =>
observable.InvalidWhen(
s => invalidCheck(), StatusCodes.Status404NotFound, errorFactory);
/// <summary>
/// If the check returns <c>true</c>, <see cref="ValidationException"/>
/// is emitted as an error with the status code 404 (Not Found).
/// Otherwise the given value is emitted.
/// </summary>
/// <typeparam name="TSource">The type of the value.</typeparam>
/// <param name="observable">The parent observable.</param>
/// <param name="invalidCheck">The invalidCheck function.</param>
/// <param name="error">The error to be used on a failed check.</param>
/// <returns>An instance of <see cref="IProviderObservable{TSource}"/>.</returns>
public static IProviderObservable <TSource> NotFoundWhen <TSource>(
this IProviderObservable <TSource> observable,
Func <bool> invalidCheck,
object error) =>
observable.InvalidWhen(
s => invalidCheck(), StatusCodes.Status404NotFound, s => error);
/// <summary>
/// If the check returns <c>true</c>, <see cref="ValidationException"/>
/// is emitted as an error with the status code 400 (Bad Request).
/// Otherwise the given value is emitted.
/// </summary>
/// <typeparam name="TSource">The type of the value.</typeparam>
/// <param name="observable">The parent observable.</param>
/// <param name="invalidCheck">The invalidCheck function.</param>
/// <param name="error">The error to be used on a failed check.</param>
/// <returns>An instance of <see cref="IProviderObservable{TSource}"/>.</returns>
public static IProviderObservable <TSource> BadRequestWhen <TSource>(
this IProviderObservable <TSource> observable,
Func <TSource, bool> invalidCheck,
object error) =>
observable.InvalidWhen(invalidCheck, StatusCodes.Status400BadRequest, s => error);
/// <summary>
/// If the check returns <c>true</c>, <see cref="ValidationException"/>
/// is emitted as an error with the status code 410 (Gone).
/// Otherwise the given value is emitted.
/// </summary>
/// <typeparam name="TSource">The type of the value.</typeparam>
/// <param name="observable">The parent observable.</param>
/// <param name="invalidCheck">The invalidCheck function.</param>
/// <param name="errorFactory">The error factory method.</param>
/// <returns>An instance of <see cref="IProviderObservable{TSource}"/>.</returns>
public static IProviderObservable <TSource> GoneWhen <TSource>(
this IProviderObservable <TSource> observable,
Func <TSource, bool> invalidCheck,
Func <TSource, object> errorFactory = null) =>
observable.InvalidWhen(invalidCheck, StatusCodes.Status410Gone, errorFactory);
/// <summary>
/// If the check returns <c>true</c>, <see cref="ValidationException"/>
/// is emitted as an error with the given status code.
/// Otherwise the given value is emitted.
/// </summary>
/// <typeparam name="TSource">The type of the value.</typeparam>
/// <param name="observable">The parent observable.</param>
/// <param name="invalidCheck">The invalidCheck function.</param>
/// <param name="statusCode">The status code of the error.</param>
/// <param name="error">The error to be used on a failed check.</param>
/// <returns>An instance of <see cref="IProviderObservable{TSource}"/>.</returns>
public static IProviderObservable <TSource> InvalidWhen <TSource>(
this IProviderObservable <TSource> observable,
Func <bool> invalidCheck,
int statusCode,
object error) =>
observable.InvalidWhen(s => invalidCheck(), statusCode, s => error);
/// <summary>
/// If the check returns <c>true</c>, <see cref="ValidationException"/>
/// is emitted as an error with the given status code.
/// Otherwise the given value is emitted.
/// </summary>
/// <typeparam name="TSource">The type of the value.</typeparam>
/// <param name="observable">The parent observable.</param>
/// <param name="invalidCheck">The invalidCheck function.</param>
/// <param name="statusCode">The status code of the error.</param>
/// <param name="errorFactory">The error factory method.</param>
/// <returns>An instance of <see cref="IProviderObservable{TSource}"/>.</returns>
public static IProviderObservable <TSource> InvalidWhen <TSource>(
this IProviderObservable <TSource> observable,
Func <bool> invalidCheck,
int statusCode,
Func <TSource, object> errorFactory = null) =>
observable.InvalidWhen(s => invalidCheck(), statusCode, errorFactory);
/// <summary>
/// If the check returns <c>true</c>, <see cref="ValidationException"/>
/// is emitted as an error with the status code 403 (Forbidden).
/// Otherwise the given value is emitted.
/// </summary>
/// <typeparam name="TSource">The type of the value.</typeparam>
/// <param name="observable">The parent observable.</param>
/// <param name="invalidCheck">The invalidCheck function.</param>
/// <param name="error">The error to be used on a failed check.</param>
/// <returns>An instance of <see cref="IProviderObservable{TSource}"/>.</returns>
public static IProviderObservable <TSource> ForbiddenWhen <TSource>(
this IProviderObservable <TSource> observable,
Func <TSource, bool> invalidCheck,
object error) =>
observable.InvalidWhen(invalidCheck, StatusCodes.Status403Forbidden, s => error);