}
  }

  companion object {
    private val PEM_REGEX = Regex("""-----BEGIN ([!-,.-~ ]*)-----([^-]*)-----END \1-----""")

    /**
     * Decodes a multiline string that contains both a [certificate][certificatePem] and a
     * [private key][privateKeyPkcs8Pem], both [PEM-encoded][rfc_7468]. A typical input string looks
     * like this:
     *
     * ```

     */
    protected Pattern metaCharsetPattern = Pattern.compile("<meta.*content\\s*=\\s*['\"].*;\\s*charset=([\\w\\d\\-_]*)['\"]\\s*/?>",
            Pattern.MULTILINE | Pattern.CASE_INSENSITIVE);

    /**
     * Map of features for the DOM parser.
     */
    protected Map<String, String> featureMap = new HashMap<>();

    /** Map of properties for the DOM parser. */

        super();
    }

    private static final Logger logger = LogManager.getLogger(XpathTransformer.class);

    private static final Pattern SPACE_PATTERN = Pattern.compile("\\s+", Pattern.MULTILINE);

    /**
     * A map of field rules, where the key is the field name and the value is the XPath expression.
     */
    protected Map<String, String> fieldRuleMap = new LinkedHashMap<>();

public class XmlTransformer extends AbstractTransformer {
    private static final Logger logger = LogManager.getLogger(XmlTransformer.class);

    private static final Pattern SPACE_PATTERN = Pattern.compile("\\s+", Pattern.MULTILINE);

    /**
     * If true, the parser will be namespace aware.
     */
    protected boolean namespaceAware;

    /**