Package net.sf.eBus.feed.historic

Interface IEHistoricSubscriber

  • All Superinterfaces:
    EObject
    public interface IEHistoricSubscriber
extends EObject
    Classes wanting to receive historic notifications from an historic subscribe feed need to implement this interface.

    An EHistoricSubscribeFeed is a hybrid objects which sits between an IEHistoricSubscriber and historic feed publishers. This historic subscribe feed collects both historic (previously published) and newly published notifications and feeds them back to the historic subscriber ordered by time. This playback also includes changes in a publisher's feed status. Method notify(ENotificationMessage, EHistoricSubscribeFeed) is used to deliver both historic and live notifications to the historic subscriber.

    Method feedStatus(PublishStatusEvent, EHistoricSubscribeFeed) reports a feed status for a particular historic publisher identified by ENotificationMessage.publisherId and PublishStatusEvent.feedState the publisher's feed state. Unlike IESubscribeFeed, feed state is tracked per publisher and not for all publishers collectively.

    If an historic subscribe feed has a fixed ending time, then when the historic subscribe feed has reached that end time or if the historic feed fails to retrieve past notification messages, then the feed calls feedDone(EHistoricSubscribeFeed.HistoricFeedState, EHistoricSubscribeFeed) to let the historic subscriber know that no more notifications or feed state changes will be delivered.

    Note: if the historic feed end time is marked as on-going EHistoricSubscribeFeed.Builder.toForever(), then historicFeedStatus is never called with a down feed state because the feed ends only when the historic subscribe feed is unsubscribed or closed.

    Author:
    Charles W. Rapp