protected String doExport(Definition definition) {
    try {
      Document document = SAXReaderUtil.createDocument();

      Element workflowDefinitionElement = document.addElement("workflow-definition");

      workflowDefinitionElement.addAttribute(
          "xmlns:xsi", "http://www.w3.org/2001/XMLSchema-instance");
      workflowDefinitionElement.addAttribute(
          "xsi:schemaLocation",
          "urn:liferay.com:liferay-workflow_"
              + _version
              + " http://www.liferay.com/dtd/liferay-workflow-definition_"
              + _schemaVersion
              + ".xsd");
      workflowDefinitionElement.addNamespace("", "urn:liferay.com:liferay-workflow_" + _version);

      Element nameElement = workflowDefinitionElement.addElement("name", _namespace);

      nameElement.addText(definition.getName());

      if (Validator.isNotNull(definition.getDescription())) {
        Element descriptionElement =
            workflowDefinitionElement.addElement("description", _namespace);

        descriptionElement.addText(definition.getDescription());
      }

      Element versionElement = workflowDefinitionElement.addElement("version", _namespace);

      versionElement.addText(String.valueOf(definition.getVersion()));

      Collection<Node> nodes = definition.getNodes();

      for (Node node : nodes) {
        NodeExporter nodeExporter = NodeExporterRegistry.getNodeExporter(node.getNodeType());

        nodeExporter.exportNode(node, workflowDefinitionElement, _namespace);
      }

      return document.formattedString();
    } catch (IOException ioe) {
      throw new SystemException("Unable to export definition", ioe);
    }
  }