add FinallyThrow

src/PipelineNet/ChainsOfResponsibility/AsyncResponsibilityChainExtensions.cs

@@ -0,0 +1,23 @@
+using System;
+
+namespace PipelineNet.ChainsOfResponsibility
+{
+    public static class AsyncResponsibilityChainExtensions
+    {
+        /// <summary>
+        /// Throws an <see cref="InvalidOperationException"/> at the end of the chain as a fallback.
+        /// A chain can only have one finally function. Calling this method more
+        /// a second time will just replace the existing finally <see cref="Func{TParameter, TResult}"/>.
+        /// </summary>
+        /// <param name="chain">The instace of <see cref="IAsyncResponsibilityChain{TParameter, TReturn}"/>.</param>
+        /// <returns>The current instance of <see cref="IAsyncResponsibilityChain{TParameter, TReturn}"/>.</returns>
+        public static IAsyncResponsibilityChain<TParameter, TReturn> FinallyThrow<TParameter, TReturn>(
+            this IAsyncResponsibilityChain<TParameter, TReturn> chain)
+        {
+            if (chain == null) throw new ArgumentNullException("chain");
+
+            return chain.Finally(_ =>
+                throw new InvalidOperationException("End of the asynchronous chain of responsibility reached. No middleware matches returned a value."));
+        }
+    }
+}

src/PipelineNet/ChainsOfResponsibility/ResponsibilityChainExtensions.cs

@@ -0,0 +1,23 @@
+using System;
+
+namespace PipelineNet.ChainsOfResponsibility
+{
+    public static class ResponsibilityChainExtensions
+    {
+        /// <summary>
+        /// Throws an <see cref="InvalidOperationException"/> at the end of the chain as a fallback.
+        /// A chain can only have one finally function. Calling this method more
+        /// a second time will just replace the existing finally <see cref="Func{TParameter, TResult}"/>.
+        /// </summary>
+        /// <param name="chain">The instace of <see cref="IResponsibilityChain{TParameter, TReturn}"/>.</param>
+        /// <returns>The current instance of <see cref="IResponsibilityChain{TParameter, TReturn}"/>.</returns>
+        public static IResponsibilityChain<TParameter, TReturn> FinallyThrow<TParameter, TReturn>(
+            this IResponsibilityChain<TParameter, TReturn> chain)
+        {
+            if (chain == null) throw new ArgumentNullException("chain");
+
+            return chain.Finally(_ =>
+                throw new InvalidOperationException("End of the chain of responsibility reached. No middleware matches returned a value."));
+        }
+    }
+}