Data subscription events

The Subscription instance exposes a few events which allow to provide control over the data stream. There are four subscription events that you can hook up:

void addBeforeBatchHandler(EventHandler<VoidArgs> handler);

void removeBeforeBatchHandler(EventHandler<VoidArgs> handler);

void addAfterBatchHandler(EventHandler<Subscription.DocumentProcessedEventArgs> handler);

void removeAfterBatchHandler(EventHandler<Subscription.DocumentProcessedEventArgs> handler);

void addBeforeAcknowledgmentHandler(EventHandler<VoidArgs> handler);

void removeBeforeAcknowledgmentHandler(EventHandler<VoidArgs> handler);

void addAfterAcknowledgmentHandler(EventHandler<Subscription.LastProcessedEtagEventArgs> handler);

void removeAfterAcknowledgmentHandler(EventHandler<Subscription.LastProcessedEtagEventArgs> handler);

Each of them is invoked on a different level of documents processing:

  • beforeBatch - called when a first document from the batch is about to be processed by handlers, if the batch is empty then the event is not raised,
  • beforeAcknowledgment - triggered after processing all documents in batch, the returned value determines if the batch can be acknowledged (default: true),
  • afterAcknowledgment - invoked after the batch processed acknowledgment had been sent to the server,
  • afterBatch - called after processing all docs from the batch.