@Override
                public void serverStarted() {
                    probePresences(service);
                }
Returns the data form included in the configure element sent by the node owner or
{@code null} if none was included or access model was defined. If the
owner just wants to set the access model to use for the node and optionally set the
list of roster groups (i.e. contacts present in the node owner roster in the
specified groups are allowed to access the node) allowed to access the node then
instead of including a data form the owner can just specify the "access" attribute
of the configure element and optionally include a list of group elements. In this case,
the method will create a data form including the specified data. This is a nice way
to accept both ways to configure a node but always returning a data form.

@param configureElement the configure element sent by the owner.
@return the data form included in the configure element sent by the node owner or
        {@code null} if none was included or access model was defined.
xmppserver/src/main/java/org/jivesoftware/openfire/pubsub/PubSubEngine.java