using System; using System.Collections.Generic; using System.Diagnostics; using System.Threading; using System.Threading.Tasks; namespace Polly.Fallback { public class FallbackPolicy : Policy, IFallbackPolicy, IsPolicy { internal FallbackPolicy(Action<Action<Context, CancellationToken>, Context, CancellationToken> exceptionPolicy, IEnumerable<ExceptionPredicate> exceptionPredicates) : base(exceptionPolicy, exceptionPredicates) { } [DebuggerStepThrough] internal override TResult ExecuteInternal<TResult>(Func<Context, CancellationToken, TResult> action, Context context, CancellationToken cancellationToken) { throw new InvalidOperationException("You have executed the generic .Execute<TResult> method on a non-generic FallbackPolicy. A non-generic FallbackPolicy only defines a fallback action which returns void; it can never return a substitute TResult value. To use FallbackPolicy to provide fallback TResult values you must define a generic fallback policy FallbackPolicy<TResult>. For example, define the policy as Policy<TResult>.Handle<Whatever>.Fallback<TResult>(/* some TResult value or Func<..., TResult> */);"); } internal FallbackPolicy(Func<Func<Context, CancellationToken, Task>, Context, CancellationToken, bool, Task> asyncExceptionPolicy, IEnumerable<ExceptionPredicate> exceptionPredicates) : base(asyncExceptionPolicy, exceptionPredicates) { } [DebuggerStepThrough] internal override Task<TResult> ExecuteAsyncInternal<TResult>(Func<Context, CancellationToken, Task<TResult>> action, Context context, CancellationToken cancellationToken, bool continueOnCapturedContext) { throw new InvalidOperationException("You have executed the generic .Execute<TResult> method on a non-generic FallbackPolicy. A non-generic FallbackPolicy only defines a fallback action which returns void; it can never return a substitute TResult value. To use FallbackPolicy to provide fallback TResult values you must define a generic fallback policy FallbackPolicy<TResult>. For example, define the policy as Policy<TResult>.Handle<Whatever>.Fallback<TResult>(/* some TResult value or Func<..., TResult> */);"); } } }