Class IQDiscoInfoHandler

  • All Implemented Interfaces:
    ChannelHandler, ClusterEventListener, Module

    public class IQDiscoInfoHandler
    extends IQHandler
    implements ClusterEventListener
    IQDiscoInfoHandler is responsible for handling disco#info requests. This class holds a map with the main entities and the associated DiscoInfoProvider. We are considering the host of the recipient JIDs as main entities. It's the DiscoInfoProvider responsibility to provide information about the JID's name together with any possible requested node.

    For example, let's have in the entities map the following entries: "localhost" and "conference.localhost". Associated with each entry we have different DiscoInfoProviders. Now we receive a disco#info request for the following JID: "room@conference.localhost" which is a disco request for a MUC room. So IQDiscoInfoHandler will look for the DiscoInfoProvider associated with the JID's host which in this case is "conference.localhost". Once we have located the provider we will delegate to the provider the responsibility to provide the info specific to the JID's name which in this case is "room". Among the information that a room could provide we could find its identity and the features it supports (e.g. 'muc_passwordprotected', 'muc_unmoderated', etc.). Finally, after we have collected all the information provided by the provider we will add it to the reply. On the other hand, if no provider was found or the provider has no information for the requested name/node then a not-found error will be returned.

    Author:
    Gaston Dombiak
    • Constructor Detail

      • IQDiscoInfoHandler

        public IQDiscoInfoHandler()
    • Method Detail

      • getInfo

        public IQHandlerInfo getInfo()
        Description copied from class: IQHandler
        Returns the handler information to help generically handle IQ packets. IQHandlers that aren't local server iq handlers (e.g. chatbots, transports, etc) return null.
        Specified by:
        getInfo in class IQHandler
        Returns:
        The IQHandlerInfo for this handler
      • handleIQ

        public org.xmpp.packet.IQ handleIQ​(org.xmpp.packet.IQ packet)
        Description copied from class: IQHandler
        Handles the received IQ packet.
        Specified by:
        handleIQ in class IQHandler
        Parameters:
        packet - the IQ packet to handle.
        Returns:
        the response to send back.
      • setServerNodeInfoProvider

        public void setServerNodeInfoProvider​(String node,
                                              DiscoInfoProvider provider)
        Sets the DiscoInfoProvider to use when a disco#info packet is sent to the server itself and the specified node. For instance, if node matches "http://jabber.org/protocol/offline" then a special DiscoInfoProvider should be use to return information about offline messages.
        Parameters:
        node - the node that the provider will handle.
        provider - the DiscoInfoProvider that will handle disco#info packets sent with the specified node.
      • removeServerNodeInfoProvider

        public void removeServerNodeInfoProvider​(String node)
        Removes the DiscoInfoProvider to use when a disco#info packet is sent to the server itself and the specified node.
        Parameters:
        node - the node that the provider was handling.
      • setProvider

        protected void setProvider​(String name,
                                   DiscoInfoProvider provider)
        Sets that a given DiscoInfoProvider will provide information about a given entity. This message must be used when new modules (e.g. MUC) are implemented and need to provide information about them.
        Parameters:
        name - the name of the entity.
        provider - the DiscoInfoProvider that will provide the entity's information.
      • removeProvider

        protected void removeProvider​(String name)
        Removes the DiscoInfoProvider related to a given entity.
        Parameters:
        name - the name of the entity.
      • addServerFeaturesProvider

        public void addServerFeaturesProvider​(ServerFeaturesProvider provider)
        Adds the features provided by the new service that implements the ServerFeaturesProvider interface. This information will be used whenever a disco for information is made against the server (i.e. the packet's target is the server). Example of features are: jabber:iq:agents, jabber:iq:time, etc.
        Parameters:
        provider - the ServerFeaturesProvider that provides new server features.
      • addServerIdentitiesProvider

        public void addServerIdentitiesProvider​(ServerIdentitiesProvider provider)
        Adds the "discoverable" identities provided by the provider whenever a disco for info is made against the server.
        Parameters:
        provider - The provider of identities.
      • removeServerIdentitiesProvider

        public void removeServerIdentitiesProvider​(ServerIdentitiesProvider provider)
        Removes this provider of identities.
        Parameters:
        provider - The provider of identities.
      • addUserIdentitiesProvider

        public void addUserIdentitiesProvider​(UserIdentitiesProvider provider)
        Adds the "discoverable" user identities provided by the provider whenever a disco for info is made against users of the server.
        Parameters:
        provider - The provider of user identities.
      • removeUserIdentitiesProvider

        public void removeUserIdentitiesProvider​(UserIdentitiesProvider provider)
        Removes this provider of user identities.
        Parameters:
        provider - The provider of identities.
      • addUserFeaturesProvider

        public void addUserFeaturesProvider​(UserFeaturesProvider provider)
        Adds the "discoverable" user features provided by the provider whenever a disco for info is made against users of the server.
        Parameters:
        provider - The provider of user features.
      • removeUserFeaturesProvider

        public void removeUserFeaturesProvider​(UserFeaturesProvider provider)
        Removes this provider of user features.
        Parameters:
        provider - The provider of features.
      • addServerFeature

        public void addServerFeature​(String namespace)
        Adds one specific feature to the information returned whenever a disco for information is made against the server.
        Parameters:
        namespace - the namespace identifying the new server feature.
      • removeServerFeature

        public void removeServerFeature​(String namespace)
        Removes a feature from the information returned whenever a disco for information is made against the server.
        Parameters:
        namespace - the namespace of the feature to be removed.
      • 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 IQHandler
        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.

        It is generally advisable that implementations of this method:
        • enrich clustered cache data, by (re)adding data from this JVM/cluster node to relevant caches
        • invoke applicable event listeners, to reflect changes in availability of data on other cluster nodes.
        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. It is generally advisable that implementations of this method:

        • restore relevant caches content, by repopulating the caches with data from this JVM/cluster node
        • invoke applicable event listeners, to reflect changes in availability of data on other cluster nodes.
        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. It is generally advisable that implementations of this method invoke applicable event listeners, to reflect changes in availability of data (related to the node that left). Often, this action is orchestrated by only one of the remaining cluster nodes: the senior member.

        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
      • setSoftwareVersionDataFormFromDiscoInfo

        public static void setSoftwareVersionDataFormFromDiscoInfo​(org.dom4j.Element query,
                                                                   LocalSession session)
        Set all Software Version data responsed by the peer for the Software information request Service Discovery (XEP-0232)
        Parameters:
        query - represented on the response of the peer
        session - represented the LocalSession with peer