async abstractions

src/M.EventBroker/IEventBroker.cs

@@ -44,4 +44,4 @@ public interface IEventBroker : IDisposable
         /// <param name="event">An <typeparamref name="TEvent"/> instance to be passed to all handlers of the event.</param>
         void Publish<TEvent>(TEvent @event);
     }
-}
+}

src/M.EventBroker/IEventBrokerAsync.cs

@@ -0,0 +1,49 @@
+using System;
+using System.Threading.Tasks;
+
+namespace M.EventBroker
+{
+    /// <summary>
+    /// Represents an event broker.
+    /// </summary>
+    public interface IEventBrokerAsync : IDisposable
+    {
+        /// <summary>
+        /// Adds subscription for events of type <typeparamref name="TEvent"/>.
+        /// </summary>
+        /// <typeparam name="TEvent">The type of the event.</typeparam>
+        /// <param name="handler">A delegate that will be invoked when event is published.</param>
+        /// <param name="filter">A delegate used to perform filtering of events before invoking the handler.</param>
+        /// <param name="onError">Called when an error is caught during execution.</param>
+        void Subscribe<TEvent>(Func<TEvent, Task> handler, Func<TEvent, Task<bool>> filter = null, Func<Exception, TEvent, Task> onError = null);
+
+        /// <summary>
+        /// Adds subscription for events of type <typeparamref name="TEvent"/>.
+        /// </summary>
+        /// <typeparam name="TEvent">The type of the event.</typeparam>
+        /// <param name="handler">An instance of IEventHandler&lt;TEvent&gt; which Handle method will be invoked when event is published.</param>
+        void Subscribe<TEvent>(IEventHandlerAsync<TEvent> handler);
+
+        /// <summary>
+        /// Removes subscription for events of type <typeparamref name="TEvent"/>.
+        /// </summary>
+        /// <typeparam name="TEvent">The type of the event.</typeparam>
+        /// <param name="handler">A delegate to remove form subscribers.</param>
+        void Unsubscribe<TEvent>(Func<TEvent, Task> handler);
+
+        /// <summary>
+        /// Removes subscription for events of type <typeparamref name="TEvent"/>.
+        /// </summary>
+        /// <typeparam name="TEvent">The type of the event.</typeparam>
+        /// <param name="handler">An instance of IEventHandler&lt;TEvent&gt; to remove form subscribers.</param>
+        void Unsubscribe<TEvent>(IEventHandlerAsync<TEvent> handler);
+
+        /// <summary>
+        /// Publishes an event of type <typeparamref name="TEvent"/>.
+        /// </summary>
+        /// <typeparam name="TEvent">The type of the event.</typeparam>
+        /// <param name="event">An <typeparamref name="TEvent"/> instance to be passed to all handlers of the event.</param>
+        /// <returns>The task object representing the asynchronous operation.</returns>
+        Task Publish<TEvent>(TEvent @event);
+    }
+}

src/M.EventBroker/IEventHandler.cs

@@ -28,4 +28,4 @@ public interface IEventHandler<TEvent>
         /// <param name="event">The event instance which handling caused the exception.</param>
         void OnError(Exception exception, TEvent @event);
     }
-}
+}

src/M.EventBroker/IEventHandlerAsync.cs

@@ -0,0 +1,34 @@
+using System;
+using System.Threading.Tasks;
+
+namespace M.EventBroker
+{
+    /// <summary>
+    /// Represents a logic for handling events.
+    /// </summary>
+    /// <typeparam name="TEvent">The type of the event.</typeparam>
+    public interface IEventHandlerAsync<TEvent>
+    {
+        /// <summary>
+        /// Handles the event.
+        /// </summary>
+        /// <param name="event">An instance of TEvent representing the event.</param>
+        /// <returns>The task object representing the asynchronous operation.</returns>
+        Task HandleAsync(TEvent @event);
+
+        /// <summary>
+        /// Returns a value indicating whether the event handler should be executed.
+        /// </summary>
+        /// <param name="event">An instance of TEvent representing the event.</param>
+        /// <returns>A value indicating whether the event handler should be executed.</returns>
+        Task<bool> ShouldHandleAsync(TEvent @event);
+
+        /// <summary>
+        /// Called when an error is caught during execution.
+        /// </summary>
+        /// <param name="exception">The exception caught.</param>
+        /// <param name="event">The event instance which handling caused the exception.</param>
+        /// <returns>The task object representing the asynchronous operation.</returns>
+        Task OnErrorAsync(Exception exception, TEvent @event);
+    }
+}

src/M.EventBroker/IEventHandlerAsyncFactory.cs

@@ -0,0 +1,17 @@
+using System.Collections.Generic;
+
+namespace M.EventBroker
+{
+    /// <summary>
+    /// Represents a provider for event handling instances.
+    /// </summary>
+    public interface IEventHandlerAsyncFactory
+    {
+        /// <summary>
+        /// Returns an event handling instances.
+        /// </summary>
+        /// <typeparam name="TEvent">The type of the event.</typeparam>
+        /// <returns>An IEnumerable of event handlers. Null is valid return value.</returns>
+        IEnumerable<IEventHandlerAsync<TEvent>> AsyncHandlersFor<TEvent>();
+    }
+}

src/M.EventBroker/IEventHandlerFactory.cs

@@ -14,4 +14,4 @@ public interface IEventHandlerFactory
         /// <returns>An IEnumerable of event handlers. Null is valid return value.</returns>
         IEnumerable<IEventHandler<TEvent>> HandlersFor<TEvent>();
     }
-}
+}

src/M.EventBroker/IHandlerRunner.cs → src/M.EventBroker/IEventHandlerRunner.cs

@@ -13,4 +13,4 @@ public interface IEventHandlerRunner : IDisposable
         /// <param name="handlers">The event handlers to run.</param>
         void Run(params Action[] handlers);
     }
-}
+}

src/M.EventBroker/IEventHandlerRunnerAsync.cs

@@ -0,0 +1,18 @@
+using System;
+using System.Threading.Tasks;
+
+namespace M.EventBroker
+{
+    /// <summary>
+    /// Represents runner of event handlers.
+    /// </summary>
+    public interface IEventHandlerRunnerAsync : IDisposable
+    {
+        /// <summary>
+        /// Runs event handlers.
+        /// </summary>
+        /// <param name="handlers">The event handlers to run.</param>
+        /// <returns>The task object representing the asynchronous operation.</returns>
+        Task RunAsync(params Func<Task>[] handlers);
+    }
+}