/// <summary>
/// Subscribes the specified aggregator to a catchup.
/// </summary>
/// <typeparam name="TProjection">The type of the projection.</typeparam>
/// <typeparam name="TData">The type of the stream's data.</typeparam>
/// <typeparam name="TCursor">The type of the cursor.</typeparam>
/// <param name="catchup">The catchup.</param>
/// <param name="aggregator">The aggregator.</param>
/// <returns>A disposable that, when disposed, unsubscribes the aggregator.</returns>
public static IDisposable Subscribe <TProjection, TData, TCursor>(
this IStreamCatchup <TData, TCursor> catchup,
IStreamAggregator <TProjection, TData> aggregator,
FetchAndSaveProjection <TProjection> manageProjection,
HandleAggregatorError <TProjection> onError = null)
{
return(catchup.SubscribeAggregator(aggregator, manageProjection, onError));
}
/// <summary>
/// Subscribes the specified aggregator to a catchup.
/// </summary>
/// <typeparam name="TProjection">The type of the projection.</typeparam>
/// <typeparam name="TData">The type of the stream's data.</typeparam>
/// <typeparam name="TCursor">The type of the cursor.</typeparam>
/// <param name="catchup">The catchup.</param>
/// <param name="aggregate">A delegate that performs an aggregate operation on projections receiving new data.</param>
/// <param name="projectionStore">The projection store.</param>
/// <returns>
/// A disposable that, when disposed, unsubscribes the aggregator.
/// </returns>
public static IDisposable Subscribe <TProjection, TData, TCursor>(
this IStreamCatchup <TData, TCursor> catchup,
AggregateAsync <TProjection, TData> aggregate,
IProjectionStore <string, TProjection> projectionStore = null)
{
return(catchup.Subscribe(Aggregator.Create(aggregate),
projectionStore.AsHandler()));
}
public static IDisposable Subscribe <TData, TCursor>(
this IStreamCatchup <TData, TCursor> catchup,
Func <IStreamBatch <TData>, Task> aggregate)
{
return(catchup.Subscribe(
Aggregator.Create <Projection <Unit, TCursor>, TData>(async(p, b) =>
{
await aggregate(b);
return p;
}),
new InMemoryProjectionStore <Projection <Unit, TCursor> >()));
}
/// <summary>
/// Runs catchup batches repeatedly with a specified interval after each batch.
/// </summary>
/// <typeparam name="TData">The type of the stream's data.</typeparam>
/// <typeparam name="TCursor">The type of the cursor.</typeparam>
/// <param name="catchup">The catchup.</param>
/// <param name="pollInterval">The amount of time to wait after each batch is processed.</param>
/// <returns>A disposable that, when disposed, stops the polling.</returns>
public static IDisposable Poll <TData, TCursor>(
this IStreamCatchup <TData, TCursor> catchup,
TimeSpan pollInterval)
{
var canceled = false;
Task.Run(async() =>
{
while (!canceled)
{
await catchup.RunSingleBatch();
await Task.Delay(pollInterval);
}
});
return(Disposable.Create(() => { canceled = true; }));
}
/// <summary>
/// Initializes a new instance of the <see cref="MultiStreamCatchup{TData, TUpstreamCursor, TDownstreamCursor}"/> class.
/// </summary>
/// <param name="upstreamCatchup">The upstream catchup.</param>
/// <exception cref="ArgumentNullException">
/// upstreamCatchup
/// or
/// manageCursor
/// </exception>
public MultiStreamCatchup(
IStreamCatchup <IStream <TData, TDownstreamCursor>, TUpstreamCursor> upstreamCatchup,
FetchAndSaveProjection <ICursor <TUpstreamCursor> > manageCursor)
{
if (upstreamCatchup == null)
{
throw new ArgumentNullException("upstreamCatchup");
}
if (manageCursor == null)
{
throw new ArgumentNullException("manageCursor");
}
this.upstreamCatchup = upstreamCatchup;
upstreamCatchup.Subscribe(
async(cursor, streams) =>
{
// ths upstream cursor is not passed here because the downstream streams have their own independent cursors
await Task.WhenAll(streams.Select(stream => RunSingleBatch(stream)));
return(cursor);
},
manageCursor);
}
/// <summary>
/// Runs the catchup query until it reaches an empty batch, then stops.
/// </summary>
public static async Task <ICursor <TCursor> > RunUntilCaughtUp <TData, TCursor>(this IStreamCatchup <TData, TCursor> catchup)
{
ICursor <TCursor> cursor;
var counter = new Counter <TData>();
using (catchup.Subscribe(async(_, batch) => counter.Count(batch), NoCursor(counter)))
{
int countBefore;
do
{
countBefore = counter.Value;
cursor = await catchup.RunSingleBatch();
} while (countBefore != counter.Value);
}
return(cursor);
}
/// <summary>
/// Initializes a new instance of the <see cref="MultiStreamCatchup{TData, TUpstreamCursor, TDownstreamCursor}"/> class.
/// </summary>
/// <param name="upstreamCatchup">The upstream catchup.</param>
/// <param name="upstreamCursor">The upstream cursor.</param>
public MultiStreamCatchup(
IStreamCatchup <IStream <TData, TDownstreamCursor>, TUpstreamCursor> upstreamCatchup,
ICursor <TUpstreamCursor> upstreamCursor) : this(upstreamCatchup, (async(streamId, update) => await update(upstreamCursor)))
{
}
