/// <summary>
/// Loads the aggregate using the latest snapshot and then applies all events
/// in the event stream from the stream revision that the snapshot was taken.
/// </summary>
/// <typeparam name="T">Snapshot type</typeparam>
/// <param name="aggregate">The aggregate.</param>
/// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
public async Task LoadFromLatestSnapshotAsync <T>(IAggregateWithSnapshot <T> aggregate)
where T : class
{
AggregateWithSnapshot <T> baseAggregate = aggregate as AggregateWithSnapshot <T>;
if (baseAggregate == null)
{
string exceptionMessage = string.Format(CultureInfo.InvariantCulture, "The supplied Aggregate did not inherit from {0}.", typeof(Aggregate).FullName);
throw new EventSourcingException(exceptionMessage);
}
// Load from the snapshot.
EventStoreSnapshot eventStoreSnapshot = await this.eventStoreProvider.ReadSnapshotAsync(aggregate.SnapshotStreamId).ConfigureAwait(false);
baseAggregate.Load(eventStoreSnapshot);
// Now load all events since the snapshot was taken.
IEventStoreStream eventStoreStream =
await this.eventStoreProvider.ReadEventsAsync(
aggregate.EventStreamId,
eventStoreSnapshot.StreamRevision,
ExpectedStreamRevision.End).ConfigureAwait(false);
baseAggregate.Load(eventStoreStream);
}
public async Task SaveSnapshotAsync <T>(IAggregateWithSnapshot <T> aggregate, Guid snapshotId)
where T : class
{
if (aggregate == null)
{
throw new ArgumentNullException(nameof(aggregate));
}
T snapshot = aggregate.TakeSnapshot();
EventStoreSnapshot eventStoreSnapshot = new EventStoreSnapshot(snapshotId, aggregate.EventStreamRevision, snapshot);
await this.eventStoreProvider.AddSnapshotAsync(aggregate.EventStreamId, aggregate.SnapshotStreamId, eventStoreSnapshot).ConfigureAwait(false);
aggregate.NumberOfEventsSinceLastSnapshot = 0;
}
internal void Load(EventStoreSnapshot eventStoreSnapshot)
{
if (eventStoreSnapshot == null)
{
throw new ArgumentNullException(nameof(eventStoreSnapshot));
}
T body = eventStoreSnapshot.Body as T;
if (body == null)
{
throw new EventSourcingException("Can't cast event type to given snapshot type.");
}
this.LoadFromSnapshot(body);
this.EventStreamRevision = eventStoreSnapshot.StreamRevision;
this.NumberOfEventsSinceLastSnapshot = 0;
}
public abstract Task AddSnapshotAsync(string eventStreamId, string snapshotStreamId, EventStoreSnapshot eventStoreSnapshot);