/** * This method is invoked remotely via jgroups. It builds a snapshot of the local subscription * state and sends it back to the requesting server by calling its receiveSubscriptions method. * * @exclude */ public void sendSubscriptions(String destinationId, Object remoteAddress) { MessageDestination destination = (MessageDestination) getDestination(destinationId); Object subscriptions; /* * Avoid trying to use the cluster stuff if this destination does not * exist or is not clustered on this server. */ if (destination == null) { if (Log.isError()) Log.getLogger(LOG_CATEGORY) .error( "Destination: " + destinationId + " does not exist on this server but we received a request for the subscription info from a peer server where the destination exists as clustered. Check the cluster configuration for this destination and make sure it matches on all servers."); return; } else if (!destination.isClustered()) { if (Log.isError()) Log.getLogger(LOG_CATEGORY) .error( "Destination: " + destinationId + " is not clustered on this server but we received a request for the subscription info from a peer server which is clustered. Check the cluster configuration for this destination and make sure it matches on all servers."); return; } RemoteSubscriptionManager subMgr = destination.getRemoteSubscriptionManager(); /* * The remote server has no subscriptions initially since it has not * started yet. We initialize the server here so that when it sends * the first add subscription request, we'll receive it. This is because * servers will not process remote add/remove subscribe requests until * they have received the subscription state from each server. */ subMgr.setSubscriptionState(Collections.EMPTY_LIST, remoteAddress); /* * To ensure that we send the remote server a clean copy of the subscription * table we need to block out the code which adds/removes subscriptions and sends * them to remote servers between here... */ try { subscribeLock.writeLock().lock(); subscriptions = destination.getSubscriptionManager().getSubscriptionState(); ClusterManager clm = getMessageBroker().getClusterManager(); clm.invokePeerToPeerOperation( getClass().getName(), destinationId, "receiveSubscriptions", new Object[] {destinationId, subscriptions}, remoteAddress); } finally { /* ... And here */ subscribeLock.writeLock().unlock(); } }