public static IServiceCollection AddMemoryEventBus(this IServiceCollection services, Assembly[] handlerAssemblies)
{
services.TryAddSingleton <MemoryEventBusStarter>();
services.TryAddSingleton <IEventPublish, MemoryEventPublish>();
ConcurrentDictionary <string, Type> eventHandlerMap = new ConcurrentDictionary <string, Type>();
foreach (var handlerType in handlerAssemblies.SelectMany(assembly => assembly.GetTypes().Where(type => type.IsClass && typeof(IEventHandler).IsAssignableFrom(type))))
{
EventHandlerAttribute eventHandlerAttribute = handlerType.GetCustomAttribute <EventHandlerAttribute>();
if (eventHandlerAttribute == null)
{
throw new InvalidOperationException($"The type {handlerType.FullName} should have {nameof(EventHandlerAttribute)} attribute");
}
if (!eventHandlerMap.TryAdd(eventHandlerAttribute.ThrowIfNull(nameof(eventHandlerAttribute)).EventName, handlerType))
{
throw new InvalidOperationException($"There are duplicate handlers for one event name {eventHandlerAttribute.EventName}");
}
services.Add(new ServiceDescriptor(handlerType, handlerType, eventHandlerAttribute.HandlerLifetime));
}
services.AddSingleton(sp => new MemoryEventDispatcher(sp, sp.GetRequiredService <ILogger <MemoryEventDispatcher> >(), eventHandlerMap));
return(services);
}
