public Object visitPanelInstance(PanelInstance instance) throws Exception {
XMLNode node = new XMLNode(PANEL_INSTANCE, currentNode);
node.addAttribute(PANELINSTANCE_ATTR_ID, instance.getInstanceId().toString());
node.addAttribute(PANELINSTANCE_ATTR_SERIALIZATION, instance.getPersistence() == null ? "" : instance.getPersistence());
node.addAttribute(PANELINSTANCE_ATTR_PROVIDER, instance.getProviderName());
if (instance.getProvider().getDriver() instanceof Exportable) {
ByteArrayOutputStream bos = new ByteArrayOutputStream();
((Exportable) instance.getProvider().getDriver()).exportContent(instance, bos);
byte[] content = bos.toByteArray();
XMLNode contentNode = new XMLNode(RAWCONTENT, node);