Horde_Xml_Element::__wakeup PHP Method

    public function __wakeup()
    {
        if ($this->_element instanceof DOMElement) {
            return true;
        }
        if ($this->_element instanceof Horde_Xml_Element) {
            $this->_element = $this->_element->getDom();
            return true;
        }
        if ($this->_serialized) {
            $this->_element = $this->_serialized;
            $this->_serialized = null;
        }
        if (is_string($this->_element)) {
            $doc = new DOMDocument();
            $doc->preserveWhiteSpace = false;
            $extract = false;
            if (substr($this->_element, 0, 5) != '<?xml') {
                $extract = true;
                $preamble = '<?xml version="1.0" encoding="UTF-8" ?><root ';
                foreach (self::$_namespaces as $prefix => $nsUri) {
                    $preamble .= " xmlns:{$prefix}=\"{$nsUri}\"";
                }
                $preamble .= '>';
                $this->_element = $preamble . $this->_element . '</root>';
            }
            $loaded = @$doc->loadXML($this->_element);
            if (!$loaded) {
                throw new Horde_Xml_Element_Exception('DOMDocument cannot parse XML: ', error_get_last());
            }
            if ($extract) {
                $newDoc = new DOMDocument();
                $this->_element = $newDoc->importNode($doc->documentElement->childNodes->item(0), true);
            } else {
                $this->_element = $doc->documentElement;
            }
            return true;
        }
        throw new InvalidArgumentException('Horde_Xml_Element initialization value must be a DOMElement, a Horde_Xml_Element, or a non-empty string; ' . (gettype($this->_element) == 'object' ? get_class($this->_element) : gettype($this->_element)) . ' given');
    }

 /**
  * Ensure that $_listItems is populated by calling the concrete implementation's
  * _buildItemsCache() method.
  */
 public function __wakeup()
 {
     parent::__wakeup();
     $this->_listItems = $this->_buildListItemCache();
 }