public static UniqueIdentifier getUniqueIdentifier(String serviceId, String nodeId, String itemId)
    {
        return new UniqueIdentifier( serviceId, nodeId, itemId );
    }
Returns a value that uniquely identifies this published item in the XMPP domain.

@param serviceId Id of the service that contains the node.
@param nodeId Node id for the published item
@param itemId Id for the published item (unique within the node)
@return Unique identifier for this item
xmppserver/src/main/java/org/jivesoftware/openfire/pubsub/PublishedItem.java