@Override
    public void addNode(Node node) {
        nodes.put(node.getUniqueIdentifier(), node);
    }
Returns true if the service is available. Use {@link #setServiceEnabled(boolean)} to
enable or disable the service.

@return true if the MUC service is available.
xmppserver/src/main/java/org/jivesoftware/openfire/pubsub/PubSubModule.java