/// <summary>
/// Create a delegate from an asynchronous (non-cancellable) action.
/// </summary>
/// <typeparam name="TAttributed">Type of object that contains methods marked with [QueryHandler].</typeparam>
/// <typeparam name="TQuery">Type of query that is handled by the QueryHandlerDelegate.</typeparam>
/// <typeparam name="TResult">Query's result type.</typeparam>
/// <param name="attributedObjectFactory">Factory delegate which produces an instance of <typeparamref name="TAttributed"/>.</param>
/// <returns>Instance of QueryHandlerDelegate.</returns>
private QueryHandlerDelegate <TResult> createNonCancellableAsyncDelegate <TAttributed, TQuery, TResult>(Func <TAttributed> attributedObjectFactory)
where TAttributed : class
where TQuery : class, IQuery <TResult>
{
Func <TAttributed, TQuery, Task <TResult> > asyncFunc = (Func <TAttributed, TQuery, Task <TResult> >)MethodInfo.CreateDelegate(typeof(Func <TAttributed, TQuery, Task <TResult> >));
return(QueryHandlerDelegateBuilder.FromDelegate(attributedObjectFactory, asyncFunc));
}
/// <summary>
/// Create a delegate from a synchronous action.
/// </summary>
/// <typeparam name="TAttributed">Type of object that contains methods marked with [QueryHandler].</typeparam>
/// <typeparam name="TQuery">Type of query that is handled by the QueryHandlerDelegate.</typeparam>
/// <typeparam name="TResult">Query's result type.</typeparam>
/// <param name="attributedObjectFactory">Factory delegate which produces an instance of <typeparamref name="TAttributed"/>.</param>
/// <returns>Instance of QueryHandlerDelegate.</returns>
private QueryHandlerDelegate <TResult> createWrappedSyncDelegate <TAttributed, TQuery, TResult>(Func <TAttributed> attributedObjectFactory)
where TAttributed : class
where TQuery : class, IQuery <TResult>
{
Func <TAttributed, TQuery, TResult> func = (Func <TAttributed, TQuery, TResult>)MethodInfo.CreateDelegate(typeof(Func <TAttributed, TQuery, TResult>));
return(QueryHandlerDelegateBuilder.FromDelegate(attributedObjectFactory, func));
}
/// <summary>
/// <para>Resolves an instance of IQueryAsyncHandler<TQuery, TResult> from the container</para>
/// <para>and converts it to a query handler delegate which can be invoked to process the query.</para>
/// </summary>
/// <typeparam name="TQuery">Type of query which is handled by the query handler.</typeparam>
/// <typeparam name="TResult">Type of query's result.</typeparam>
/// <returns>Instance of <see cref="QueryHandlerDelegate{TResult}"/> which executes the query handler processing.</returns>
public QueryHandlerDelegate <TResult> ResolveQueryHandler <TQuery, TResult>() where TQuery : class, IQuery <TResult>
{
try
{
IQueryAsyncHandler <TQuery, TResult> queryAsyncHandler = _containerAdapter.Resolve <IQueryAsyncHandler <TQuery, TResult> >();
if (queryAsyncHandler == null)
{
// No handlers are resolved. Throw exception.
throw ExceptionBuilder.NoQueryHandlerResolvedException(typeof(TQuery));
}
return(QueryHandlerDelegateBuilder.FromQueryHandler(queryAsyncHandler));
}
catch (Exception ex)
{
// No handlers are resolved. Throw exception.
throw ExceptionBuilder.NoQueryHandlerResolvedException(typeof(TQuery), ex);
}
}
/// <summary>
/// Register query async handler.
/// </summary>
/// <typeparam name="TQuery">Type of query to be handled.</typeparam>
/// <typeparam name="TResult">Type of query's result.</typeparam>
/// <param name="queryAsyncHandlerFactory">Factory which will provide an instance of a query handler that handles the specified <typeparamref name="TQuery"/> query.</param>
public void Register <TQuery, TResult>(Func <IQueryAsyncHandler <TQuery, TResult> > queryAsyncHandlerFactory) where TQuery : class, IQuery <TResult>
{
if (queryAsyncHandlerFactory == null)
{
throw new ArgumentNullException(nameof(queryAsyncHandlerFactory));
}
Type queryType = typeof(TQuery);
QueryHandlerDelegate <TResult> handleQueryDelegate;
if (_queryHandlerDelegatesByQueryType.TryGetValue(queryType, out handleQueryDelegate))
{
throw new InvalidOperationException($"Duplicate query handler registered for {queryType.Name}.");
}
QueryHandlerDelegate <TResult> newHandleQueryDelegate = QueryHandlerDelegateBuilder.FromFactory(queryAsyncHandlerFactory);
_queryHandlerDelegatesByQueryType.Add(queryType, newHandleQueryDelegate);
}
