/// <summary>
/// Add the ability to resolve an instance of <typeparam name="T"></typeparam>
/// Without adding a resolver the bus will attempt to find and call the default
/// constructor to create an instance when adding handlers from assemblies.
/// Use <see cref="AddResolver{T}"/> if your handler does not have default constructor
/// or you want to re-use an instance.
/// </summary>
/// <example>
/// <code>
/// // For type MessageHandler, call the c'tor that takes an IBus parameter
/// bus.AddResolver(()=> new MessageHandler(bus));
/// // find all the handlers in assemblies named *handlers.dll" in the current directory in the namespace
/// "MyCorp.MessageHandlers
/// bus.AddHandlersAndTranslators(Directory.GetCurrentDirectory(), "*handlers.dll", "MyCorp.MessageHandlers");
/// </code>
/// </example>
/// <typeparam name="T">The type of instance to resolve. Typically of type IConsumer{TMessage}</typeparam>
/// <param name="bus">The <seealso cref="IBus"/> instance this will apply to</param>
/// <param name="resolver">A delegate that returns an instance of <typeparamref name="T"/></param>
public static void AddResolver <T>(this Patterns.Bus bus, Func <T> resolver)
{
if (!busResolverDictionaries.ContainsKey(bus))
{
busResolverDictionaries.Add(bus, new Dictionary <Type, Delegate>());
}
var dictionary = busResolverDictionaries[bus];
dictionary[typeof(T)] = resolver;
}
public static void SetServiceLocator(this Patterns.Bus bus, IServiceLocator serviceLocator)
{
if (bus == null)
{
throw new ArgumentNullException(nameof(bus));
}
if (serviceLocator == null)
{
throw new ArgumentNullException(nameof(serviceLocator));
}
if (!busServiceLocators.ContainsKey(bus))
{
busServiceLocators.Add(bus, serviceLocator);
}
else
{
busServiceLocators[bus] = serviceLocator;
}
}
/// <summary>
/// Dynamically load message handlers by filename in a specific directory.
/// </summary>
/// <example>
/// <code>
/// // find all the handlers in assemblies named *handlers.dll" in the current directory in the namespace
/// "MyCorp.MessageHandlers
/// bus.AddHandlersAndTranslators(Directory.GetCurrentDirectory(), "*handlers.dll", "MyCorp.MessageHandlers");
/// </code>
/// </example>
/// <param name="bus">The <seealso cref="IBus"/> instance this will apply to</param>
/// <param name="directory">What directory to search</param>
/// <param name="wildcard">What filenames to search</param>
/// <param name="namespace">Include IConsumers{TMessage} within this namespace</param>
public static void AddHandlersAndTranslators(this Patterns.Bus bus, string directory, string wildcard, string @namespace)
{
if (!busResolverDictionaries.ContainsKey(bus))
{
busResolverDictionaries.Add(bus, new Dictionary <Type, Delegate>());
}
IServiceLocator serviceLocator = busServiceLocators.ContainsKey(bus) ? busServiceLocators[bus] : new ActivatorServiceLocator();
IEnumerable <Type> consumerTypes = typeof(IConsumer <>).ByImplementedInterfaceInDirectory(directory, wildcard, @namespace);
foreach (var consumerType in consumerTypes)
{
var pipeImplementationInterface =
consumerType.GetInterfaces()
.FirstOrDefault(t => !t.IsGenericTypeDefinition && t.GetGenericTypeDefinition() == typeof(IPipe <,>));
if (pipeImplementationInterface != null)
{
var translatorType = consumerType;
var messageTypes = pipeImplementationInterface.GetGenericTypeArguments();
// get instance of pipe
var translatorInstance = busResolverDictionaries[bus].ContainsKey(translatorType)
? InvokeFunc(busResolverDictionaries[bus][translatorType])
: serviceLocator.GetInstance(translatorType);
// get instance of the helper that will help add specific handler
// code to the bus.
var helperType1 = typeof(PipeAttachConsumerHelper <,>).MakeGenericType(messageTypes);
var helperType1Instance = Activator.CreateInstance(helperType1);
var attachConsumerMethodInfo = helperType1.GetMethod("AttachConsumer");
attachConsumerMethodInfo.Invoke(helperType1Instance, new[] { translatorInstance, bus });
var inType = messageTypes[0];
var helperType = typeof(BusAddhHandlerHelper <>).MakeGenericType(inType);
var helperInstance = Activator.CreateInstance(helperType);
var addHandlerMethodInfo = helperType.GetMethod("AddHandler");
addHandlerMethodInfo.Invoke(helperInstance, new[] { bus, translatorInstance });
}
else
{
var consumerImplementationInterface =
consumerType.GetInterfaces()
.FirstOrDefault(t => !t.IsGenericTypeDefinition && t.GetGenericTypeDefinition() == typeof(IConsumer <>));
Debug.Assert(consumerImplementationInterface != null,
"Unexpected state enumerating implementations of IConsumer<T>");
var messageTypes = consumerImplementationInterface.GetGenericTypeArguments();
var helperType = typeof(BusAddhHandlerHelper <>).MakeGenericType(messageTypes);
var helperInstance = Activator.CreateInstance(helperType);
var addHandlerMethodInfo = helperType.GetMethod("AddHandler");
var handlerInstance = busResolverDictionaries[bus].ContainsKey(consumerType)
? InvokeFunc(busResolverDictionaries[bus][consumerType])
: serviceLocator.GetInstance(consumerType);
addHandlerMethodInfo.Invoke(helperInstance, new[] { bus, handlerInstance });
}
}
}
