/// <summary>
/// Emits the given domain event, adding the aggregate root's <see cref="Id"/> and a sequence number to its metadata, along with some type information
/// </summary>
protected void Emit <TAggregateRoot>(DomainEvent <TAggregateRoot> e) where TAggregateRoot : AggregateRoot
{
if (e == null)
{
throw new ArgumentNullException("e", "Can't emit null!");
}
if (string.IsNullOrWhiteSpace(Id))
{
throw new InvalidOperationException(
string.Format(
"Attempted to emit event {0} from aggregate root {1}, but it has not yet been assigned an ID!",
e, GetType()));
}
var eventType = e.GetType();
var emitterInterface = typeof(IEmit <>).MakeGenericType(eventType);
if (!emitterInterface.IsAssignableFrom(GetType()))
{
throw new InvalidOperationException(
string.Format(
"Attempted to emit event {0} but the aggregate root {1} does not implement IEmit<{2}>",
e, GetType().Name, e.GetType().Name));
}
if (UnitOfWork == null)
{
throw new InvalidOperationException(string.Format("Attempted to emit event {0}, but the aggreate root does not have a unit of work!", e));
}
if (ReplayState != ReplayState.None)
{
throw new InvalidOperationException(string.Format("Attempted to emit event {0}, but the aggreate root's replay state is {1}! - events can only be emitted when the root is not applying events", e, ReplayState));
}
if (!typeof(TAggregateRoot).IsAssignableFrom(GetType()))
{
throw new InvalidOperationException(
string.Format("Attempted to emit event {0} which is owned by {1} from aggregate root of type {2}",
e, typeof(TAggregateRoot), GetType()));
}
var now = Time.UtcNow();
var sequenceNumber = CurrentSequenceNumber + 1;
e.Meta.Merge(CurrentCommandMetadata ?? new Metadata());
e.Meta[DomainEvent.MetadataKeys.AggregateRootId] = Id;
e.Meta[DomainEvent.MetadataKeys.TimeUtc] = now.ToString("u");
e.Meta[DomainEvent.MetadataKeys.SequenceNumber] = sequenceNumber.ToString(Metadata.NumberCulture);
e.Meta.TakeFromAttributes(eventType);
e.Meta.TakeFromAttributes(GetType());
try
{
ApplyEvent(e, ReplayState.EmitApply);
}
catch (Exception exception)
{
throw new ApplicationException(string.Format(@"Could not apply event {0} to {1} - please check the inner exception, and/or make sure that the aggregate root type is PUBLIC", e, this), exception);
}
UnitOfWork.AddEmittedEvent(this, e);
EventEmitted(e);
}