public CommandScheduler(
IEventSourcedRepository <TAggregate> repository,
ICommandPreconditionVerifier preconditionVerifier = null)
{
if (repository == null)
{
throw new ArgumentNullException("repository");
}
this.repository = repository;
this.preconditionVerifier = preconditionVerifier ??
Configuration.Current.Container.Resolve <ICommandPreconditionVerifier>();
}
public static async Task ApplyScheduledCommand <TAggregate>(
this IEventSourcedRepository <TAggregate> repository,
IScheduledCommand <TAggregate> scheduled,
ICommandPreconditionVerifier preconditionVerifier = null)
where TAggregate : class, IEventSourced
{
TAggregate aggregate = null;
Exception exception = null;
if (scheduled.Result is CommandDelivered)
{
return;
}
try
{
if (preconditionVerifier != null &&
!await preconditionVerifier.IsPreconditionSatisfied(scheduled))
{
await FailScheduledCommand(repository,
scheduled,
new PreconditionNotMetException(scheduled.DeliveryPrecondition));
return;
}
aggregate = await repository.GetLatest(scheduled.AggregateId);
if (aggregate == null)
{
if (scheduled.Command is ConstructorCommand <TAggregate> )
{
var ctor = typeof(TAggregate).GetConstructor(new[] { scheduled.Command.GetType() });
aggregate = (TAggregate)ctor.Invoke(new[] { scheduled.Command });
}
else
{
// TODO: (ApplyScheduledCommand) this should probably be a different exception type.
throw new ConcurrencyException(
string.Format("No {0} was found with id {1} so the command could not be applied.",
typeof(TAggregate).Name, scheduled.AggregateId),
new IEvent[] { scheduled });
}
}
else
{
await aggregate.ApplyAsync(scheduled.Command);
}
await repository.Save(aggregate);
scheduled.Result = new CommandSucceeded(scheduled);
return;
}
catch (Exception ex)
{
exception = ex;
}
await FailScheduledCommand(repository, scheduled, exception, aggregate);
}
