/// <summary>
/// Schedules a command for asynchronous and, optionally, deferred delivery.
/// </summary>
/// <typeparam name="TCommand">The type of the command.</typeparam>
/// <param name="command">The command.</param>
/// <param name="due">The time when the command should be delivered. If this is null, the scheduler will deliver it as soon as possible.</param>
/// <exception cref="System.ArgumentNullException">command</exception>
protected async Task ScheduleCommandAsync <TCommand>(TCommand command,
DateTimeOffset?due = null)
where TCommand : class, ICommand <T>
{
if (command == null)
{
throw new ArgumentNullException(nameof(command));
}
var commandScheduledEvent = new CommandScheduled <T>
{
AggregateId = Id,
Command = command,
DueTime = due
};
var scheduledCommand = new ScheduledCommand <T>(
command,
Id,
due,
new EventHasBeenRecordedPrecondition(commandScheduledEvent.ETag, Id));
await Configuration.Current
.CommandScheduler <T>()
.Schedule(scheduledCommand);
RecordEvent(commandScheduledEvent);
}
internal static IScheduledCommand <TAggregate> CreateScheduledCommand <TCommand, TAggregate>(
Guid aggregateId,
TCommand command,
DateTimeOffset?dueTime,
IEvent deliveryDependsOn = null)
where TCommand : ICommand <TAggregate> where TAggregate : IEventSourced
{
ScheduledCommandPrecondition precondition = null;
if (deliveryDependsOn != null)
{
if (deliveryDependsOn.AggregateId == Guid.Empty)
{
throw new ArgumentException("An AggregateId must be set on the event on which the scheduled command depends.");
}
if (String.IsNullOrWhiteSpace(deliveryDependsOn.ETag))
{
deliveryDependsOn.IfTypeIs <Event>()
.ThenDo(e => e.ETag = Guid.NewGuid().ToString("N"))
.ElseDo(() => { throw new ArgumentException("An ETag must be set on the event on which the scheduled command depends."); });
}
precondition = new ScheduledCommandPrecondition
{
AggregateId = deliveryDependsOn.AggregateId,
ETag = deliveryDependsOn.ETag
};
}
if (String.IsNullOrEmpty(command.ETag))
{
command.IfTypeIs <Command>()
.ThenDo(c => c.ETag = CommandContext.Current
.IfNotNull()
.Then(ctx => ctx.NextETag(aggregateId.ToString("N")))
.Else(() => Guid.NewGuid().ToString("N")));
}
var scheduledCommand = new CommandScheduled <TAggregate>
{
Command = command,
DueTime = dueTime,
AggregateId = aggregateId,
SequenceNumber = -DateTimeOffset.UtcNow.Ticks,
DeliveryPrecondition = precondition
};
return(scheduledCommand);
}
/// <summary>
/// Schedules a command for asynchronous and, optionally, deferred delivery.
/// </summary>
/// <typeparam name="TCommand">The type of the command.</typeparam>
/// <param name="command">The command.</param>
/// <param name="due">The time when the command should be delivered. If this is null, the scheduler will deliver it as soon as possible.</param>
/// <exception cref="System.ArgumentNullException">command</exception>
protected void ScheduleCommand <TCommand>(TCommand command,
DateTimeOffset?due = null)
where TCommand : class, ICommand <T>
{
if (command == null)
{
throw new ArgumentNullException("command");
}
var scheduled = new CommandScheduled <T>
{
Command = command,
DueTime = due
};
RecordEvent(scheduled);
}