org.jivesoftware.openfire.handler
Class PresenceUpdateHandler

java.lang.Object
  org.jivesoftware.openfire.container.BasicModule
      org.jivesoftware.openfire.handler.PresenceUpdateHandler

All Implemented Interfaces:

ChannelHandler, ClusterEventListener, Module

public class PresenceUpdateHandler
extends BasicModule
implements ChannelHandler, ClusterEventListener

Implements the presence protocol. Clients use this protocol to update presence and roster information.

The handler must properly detect the presence type, update the user's roster, and inform presence subscribers of the session's updated presence status. Presence serves many purposes in Jabber so this handler will likely be the most complex of all handlers in the server.

There are four basic types of presence updates:

• Simple presence updates - addressed to the server (or to address), these updates are properly addressed by the server, and multicast to interested subscribers on the user's roster. An empty, missing, or "unavailable" type attribute indicates a simple update (there is no "available" type although it should be accepted by the server.
• Directed presence updates - addressed to particular jabber entities, these presence updates are properly addressed and directly delivered to the entity without broadcast to roster subscribers. Any update type is possible except those reserved for subscription requests.
• Subscription requests - these updates request presence subscription status changes. Such requests always affect the roster. The server must:
  • update the roster with the proper subscriber info
  • push the roster changes to the user
  • forward the update to the correct parties.
  The valid types include "subscribe", "subscribed", "unsubscribed", and "unsubscribe".
• XMPPServer probes - Provides a mechanism for servers to query the presence status of users on another server. This allows users to immediately know the presence status of users when they come online rather than way for a presence update broadcast from the other server or tracking them as they are received. Requires S2S capabilities.

Author:

Iain Shigeoka

Field Summary

static String

PRESENCE_CACHE_NAME

Constructor Summary

PresenceUpdateHandler()

Method Summary

Presence	createSubscribePresence(JID senderAddress, JID targetJID, boolean isSubscribe)
void	directedPresenceSent(Presence update, JID handlerJID, String jid) Notification method sent to this handler when a user has sent a directed presence to an entity.
boolean	hasDirectPresence(JID ownerJID, JID recipientJID)
void	initialize(XMPPServer server) Initializes the basic module.
void	joinedCluster() Notification event indicating that this JVM is now part of a cluster.
void	joinedCluster(byte[] nodeID) Notification event indicating that another JVM is now part of a cluster.
void	leftCluster() Notification event indicating that this JVM is no longer part of the cluster.
void	leftCluster(byte[] nodeID) Notification event indicating that another JVM is no longer part of the cluster.
void	markedAsSeniorClusterMember() Notification event indicating that this JVM is now the senior cluster member.
void	process(Packet packet) Process an XMPP packet.
void	process(Presence presence) Handle presence updates that affect roster subscriptions.
void	removedExpiredPresences() Removes directed presences sent to entities that are no longer available.

Methods inherited from class org.jivesoftware.openfire.container.BasicModule

destroy, getName, start, stop

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

PRESENCE_CACHE_NAME

public static final String PRESENCE_CACHE_NAME

See Also:

Constant Field Values

Constructor Detail

PresenceUpdateHandler

public PresenceUpdateHandler()

Method Detail

process

public void process(Packet packet)
             throws UnauthorizedException,
                    PacketException

Description copied from interface: ChannelHandler

Process an XMPP packet.

Specified by:

process in interface ChannelHandler

Parameters:

packet - a packet to process.

Throws:

UnauthorizedException - if not allowed to process the packet.

PacketException - thrown if the packet is malformed (results in the sender's session being shutdown).

process

public void process(Presence presence)
             throws PacketException

Handle presence updates that affect roster subscriptions.

Parameters:

presence - The presence presence to handle

Throws:

PacketException - if the packet is null or the packet could not be routed.

createSubscribePresence

public Presence createSubscribePresence(JID senderAddress,
                                        JID targetJID,
                                        boolean isSubscribe)

directedPresenceSent

public void directedPresenceSent(Presence update,
                                 JID handlerJID,
                                 String jid)

Notification method sent to this handler when a user has sent a directed presence to an entity. If the sender of the presence is local (to this server) and the target entity does not belong to the user's roster then update the registry of sent directed presences by the user.

Parameters:

update - the directed Presence sent by the user to an entity.

handlerJID - the JID of the handler that will receive/handle/process the sent packet.

jid - the receipient specified in the packet to handle.

hasDirectPresence

public boolean hasDirectPresence(JID ownerJID,
                                 JID recipientJID)

removedExpiredPresences

public void removedExpiredPresences()

Removes directed presences sent to entities that are no longer available.

initialize

public void initialize(XMPPServer server)

Description copied from class: BasicModule

Initializes the basic module.

Inheriting classes that choose to override this method MUST call this initialize() method before accessing BasicModule resources.

Specified by:

initialize in interface Module

Overrides:

initialize in class BasicModule

Parameters:

server - the server hosting this module.

joinedCluster

public void joinedCluster()

Description copied from interface: ClusterEventListener

Notification event indicating that this JVM is now part of a cluster. At this point the XMPPServer.getNodeID() holds the new nodeID value.

When joining the cluster as the senior cluster member the ClusterEventListener.markedAsSeniorClusterMember() event will be sent right after this event.

At this point the CacheFactory holds clustered caches. That means that modifications to the caches will be reflected in the cluster. The clustered caches were just obtained from the cluster and no local cached data was automatically moved.

Specified by:

joinedCluster in interface ClusterEventListener

joinedCluster

public void joinedCluster(byte[] nodeID)

Description copied from interface: ClusterEventListener

Notification event indicating that another JVM is now part of a cluster.

At this point the CacheFactory of the new node holds clustered caches. That means that modifications to the caches of this JVM will be reflected in the cluster and in particular in the new node.

Specified by:

joinedCluster in interface ClusterEventListener

Parameters:

nodeID - ID of the node that joined the cluster.

leftCluster

public void leftCluster()

Description copied from interface: ClusterEventListener

Notification event indicating that this JVM is no longer part of the cluster. This could happen when disabling clustering support, removing the enterprise plugin that provides clustering support or connection to cluster got lost.

Moreover, if we were in a "split brain" scenario (ie. separated cluster islands) and the island were this JVM belonged was marked as "old" then all nodes of that island will get the left cluster event and joined cluster events. That means that caches will be reset and thus will need to be repopulated again with fresh data from this JVM. This also includes the case where this JVM was the senior cluster member and when the islands met again then this JVM stopped being the senior member.

At this point the CacheFactory holds local caches. That means that modifications to the caches will only affect this JVM.

Specified by:

leftCluster in interface ClusterEventListener

leftCluster

public void leftCluster(byte[] nodeID)

Description copied from interface: ClusterEventListener

Notification event indicating that another JVM is no longer part of the cluster. This could happen when disabling clustering support, removing the enterprise plugin that provides clustering support or connection to cluster got lost.

Moreover, if we were in a "split brain" scenario (ie. separated cluster islands) and the island were the other JVM belonged was marked as "old" then all nodes of that island will get the left cluster event and joined cluster events. That means that caches will be reset and thus will need to be repopulated again with fresh data from this JVM. This also includes the case where the other JVM was the senior cluster member and when the islands met again then the other JVM stopped being the senior member.

At this point the CacheFactory of the leaving node holds local caches. That means that modifications to the caches of this JVM will not affect the leaving node but other cluster members.

Specified by:

leftCluster in interface ClusterEventListener

Parameters:

nodeID - ID of the node that is left the cluster.

markedAsSeniorClusterMember

public void markedAsSeniorClusterMember()

Description copied from interface: ClusterEventListener

Notification event indicating that this JVM is now the senior cluster member. This could either happen when initially joining the cluster or when the senior cluster member node left the cluster and this JVM was marked as the new senior cluster member.

Moreover, in the case of a "split brain" scenario (ie. separated cluster islands) each island will have its own senior cluster member. However, when the islands meet again there could only be one senior cluster member so one of the senior cluster members will stop playing that role. When that happens the JVM no longer playing that role will receive the ClusterEventListener.leftCluster() and ClusterEventListener.joinedCluster() events.

Specified by:

markedAsSeniorClusterMember in interface ClusterEventListener