@Override
    public Iterator<DiscoServerItem> getItems() {
        // Check if the service is disabled. Info is not available when disabled.
        if (!isServiceEnabled()) {
            return null;
        }
        ArrayList<DiscoServerItem> items = new ArrayList<>();
        final DiscoServerItem item = new DiscoServerItem(new JID(
            getServiceDomain()), "Publish-Subscribe service", null, null, this,
            this);
        items.add(item);
        return items.iterator();
    }
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