Package org.forgerock.openig.tools.notifications.ws.link

Class TopicMultiplexerAmLink

java.lang.Object
org.forgerock.openig.tools.notifications.ws.link.TopicMultiplexerAmLink
All Implemented Interfaces:
AmLink, AmLinkListener, AmLinkListener.ResilientAmLinkListener
public class TopicMultiplexerAmLink extends Object implements AmLink, AmLinkListener.ResilientAmLinkListener
Multiplex topic registration on top of a AmLink.

As AM does not manage multiple subscriptions to the same topic from a client, this class has to do the subscription multiplexing itself. In other words, it maintains a map of subscribed TopicMultiplexerAmLink.Topics, each of which has a reference counter used to detect when an un-registration action needs to be performed.

The first time a topic is subscribed to, this class sends a subscription message to AM and waits for the acknowledgment. Every subsequent subscription to the same topic will reuse the same "connection" without sending a subscription request. Inversely, no un-subscription request is sent to AM until the last reference is removed.

The following issues may occur:

  • 2 (un)subscriptions at the same time: a lock prevents this.
  • A topic is subscribed, then unsubscribed before the subscription promise fulfillment: Wait for the subscription promise to complete before un-subscribing
  • A topic is subscribed, the subscription promise failed. Then the subscription is removed from the topic list
  • A topic is un-subscribed, the un-subscription promise failed. The the topic is still considered as subscribed

  • Method Details

    • start

      public Promise<Void,Exception> start()
      Description copied from interface: AmLink
      Start the AmLink. The AmLink is considered ready for use only when the resulting promise has successfully completed. In case of a failed promise, the instance is considered as already closed.

      Note that notifications are guaranteed to be received AT LEAST once. Duplicate notification may occur.

      Specified by:
      start in interface AmLink
      Returns:
      A promise of this AmLink's start completion.

    • onReopen

      public void onReopen()
      Description copied from interface: AmLinkListener.ResilientAmLinkListener
      The handler to call on connection reopening. Can only be called after onDisconnection call, and will be called before any (un)subscribe promise completes.
      Specified by:
      onReopen in interface AmLinkListener.ResilientAmLinkListener

    • onDisconnection

      public void onDisconnection()
      Description copied from interface: AmLinkListener
      The handler to call in case of a disconnection. When this handler is called, the instance is considered as closed. Can only be called after the start promise successful completion, and before every ongoing (un)subscribe promise failure.
      Specified by:
      onDisconnection in interface AmLinkListener

    • onNotification

      public void onNotification(Notification notification)
      Description copied from interface: AmLinkListener
      The notification handler, will receive all notifications sent by AM. Duplicate notifications may occur.
      Specified by:
      onNotification in interface AmLinkListener
      Parameters:
      notification - the received notification

    • close

      public Promise<Void,Exception> close()
      Description copied from interface: AmLink
      Close the AmLink and its associated resources. The instance can't be reused afterward.
      Specified by:
      close in interface AmLink
      Returns:
      A promise indicating the AmLink has been closed

    • subscribe

      public Promise<Void,Exception> subscribe(String topicName)
      Description copied from interface: AmLink
      Subscribe to an AM topic. After successful subscription, the notification consumer (supplied in will begin receiving notifications on this topic.
      Specified by:
      subscribe in interface AmLink
      Parameters:
      topicName - The AM topic to subscribe to.
      Returns:
      A promise of a successful subscription to the AM topic.

    • unsubscribe

      public Promise<Void,Exception> unsubscribe(String topicName)
      Description copied from interface: AmLink
      Unsubscribe from an AM topic. After successful unsubscribe request, the notification consumer will stop receiving notifications on this topic.
      Specified by:
      unsubscribe in interface AmLink
      Parameters:
      topicName - The AM topic to un-subscribe from.
      Returns:
      A promise of a successful un-subscription to the AM topic.

    • asSupplier

      public static AmLink.ResilientAmLinkSupplier asSupplier(AmLink.ResilientAmLinkSupplier amLinkSupplier)
      Create a supplier that adds a TopicMultiplexerAmLink in front of a resilient AmLink.
      Parameters:
      amLinkSupplier - the wrapped resilient AmLink.
      Returns:
      a supplier.