/**
  * Set the presence of this session
  *
  * @param presence The presence for the session
  */
 public void setPresence(Presence presence) {
   Presence oldPresence = this.presence;
   this.presence = presence;
   if (oldPresence.isAvailable() && !this.presence.isAvailable()) {
     // The client is no longer available
     sessionManager.sessionUnavailable(this);
     // Mark that the session is no longer initialized. This means that if the user sends
     // an available presence again the session will be initialized again thus receiving
     // offline messages and offline presence subscription requests
     setInitialized(false);
     // Notify listeners that the session is no longer available
     PresenceEventDispatcher.unavailableSession(this, presence);
   } else if (!oldPresence.isAvailable() && this.presence.isAvailable()) {
     // The client is available
     sessionManager.sessionAvailable(this, presence);
     wasAvailable = true;
     // Notify listeners that the session is now available
     PresenceEventDispatcher.availableSession(this, presence);
   } else if (this.presence.isAvailable()
       && oldPresence.getPriority() != this.presence.getPriority()) {
     // The client has changed the priority of his presence
     sessionManager.changePriority(this, oldPresence.getPriority());
     // Notify listeners that the priority of the session/resource has changed
     PresenceEventDispatcher.presenceChanged(this, presence);
   } else if (this.presence.isAvailable()) {
     // Notify listeners that the show or status value of the presence has changed
     PresenceEventDispatcher.presenceChanged(this, presence);
   }
   if (ClusterManager.isClusteringStarted()) {
     // Track information about the session and share it with other cluster nodes
     Cache<String, ClientSessionInfo> cache = SessionManager.getInstance().getSessionInfoCache();
     cache.put(getAddress().toString(), new ClientSessionInfo(this));
   }
 }
  public void process(Presence presence) throws PacketException {
    try {
      JID senderJID = presence.getFrom();
      JID recipientJID = presence.getTo();
      Presence.Type type = presence.getType();

      // Reject presence subscription requests sent to the local server itself.
      if (recipientJID == null || recipientJID.toString().equals(serverName)) {
        if (type == Presence.Type.subscribe) {
          Presence reply = new Presence();
          reply.setTo(senderJID);
          reply.setFrom(recipientJID);
          reply.setType(Presence.Type.unsubscribed);
          deliverer.deliver(reply);
        }
        return;
      }

      try {
        Roster senderRoster = getRoster(senderJID);
        if (senderRoster != null) {
          manageSub(recipientJID, true, type, senderRoster);
        }
        Roster recipientRoster = getRoster(recipientJID);
        boolean recipientSubChanged = false;
        if (recipientRoster != null) {
          recipientSubChanged = manageSub(senderJID, false, type, recipientRoster);
        }

        // Do not forward the packet to the recipient if the presence is of type subscribed
        // and the recipient user has not changed its subscription state.
        if (!(type == Presence.Type.subscribed
            && recipientRoster != null
            && !recipientSubChanged)) {

          // If the user is already subscribed to the *local* user's presence then do not
          // forward the subscription request. Also, do not send an auto-reply on behalf
          // of the user. This presence stanza is the user's server know that it MUST no
          // longer send notification of the subscription state change to the user.
          // See http://tools.ietf.org/html/rfc3921#section-7 and/or OF-38
          if (type == Presence.Type.subscribe && recipientRoster != null && !recipientSubChanged) {
            try {
              RosterItem.SubType subType = recipientRoster.getRosterItem(senderJID).getSubStatus();
              if (subType == RosterItem.SUB_FROM || subType == RosterItem.SUB_BOTH) {
                return;
              }
            } catch (UserNotFoundException e) {
              // Weird case: Roster item does not exist. Should never happen
              Log.error(
                  "User does not exist while trying to update roster item. "
                      + "This should never happen (this indicates a programming "
                      + "logic error). Processing stanza: "
                      + presence.toString(),
                  e);
            }
          }

          // Try to obtain a handler for the packet based on the routes. If the handler is
          // a module, the module will be able to handle the packet. If the handler is a
          // Session the packet will be routed to the client. If a route cannot be found
          // then the packet will be delivered based on its recipient and sender.
          List<JID> jids = routingTable.getRoutes(recipientJID, null);
          if (!jids.isEmpty()) {
            for (JID jid : jids) {
              Presence presenteToSend = presence.createCopy();
              // Stamp the presence with the user's bare JID as the 'from' address,
              // as required by section 8.2.5 of RFC 3921
              presenteToSend.setFrom(senderJID.toBareJID());
              routingTable.routePacket(jid, presenteToSend, false);
            }
          } else {
            deliverer.deliver(presence.createCopy());
          }

          if (type == Presence.Type.subscribed) {
            // Send the presence of the local user to the remote user. The remote user
            // subscribed to the presence of the local user and the local user accepted
            JID prober =
                localServer.isLocal(recipientJID)
                    ? new JID(recipientJID.toBareJID())
                    : recipientJID;
            presenceManager.probePresence(prober, senderJID);
            PresenceEventDispatcher.subscribedToPresence(recipientJID, senderJID);
          }
        }

        if (type == Presence.Type.unsubscribed) {
          // Send unavailable presence from all of the local user's available resources
          // to the remote user
          presenceManager.sendUnavailableFromSessions(recipientJID, senderJID);
          PresenceEventDispatcher.unsubscribedToPresence(senderJID, recipientJID);
        }
      } catch (SharedGroupException e) {
        Presence result = presence.createCopy();
        JID sender = result.getFrom();
        result.setFrom(presence.getTo());
        result.setTo(sender);
        result.setError(PacketError.Condition.not_acceptable);
        deliverer.deliver(result);
      }
    } catch (Exception e) {
      Log.error(LocaleUtils.getLocalizedString("admin.error"), e);
    }
  }