public function loadTagsFromXMLObject($xml_obj)
 {
     $this->original_tags = array();
     $this->tags = array();
     if (count($xml_obj->{'tag'}) > 0) {
         foreach ($xml_obj->{'tag'} as $value) {
             $tag = new HighriseTag($value->{'id'}, $value->{'name'});
             $original_tags[$tag->getName()] = 1;
             $this->addTag($tag);
         }
     }
 }
 public function add_tag($tag)
 {
     if ($tag instanceof HighriseTag && !isset($this->tags[$tag->get_name()])) {
         $this->tags[$tag->get_name()] = $tag;
         $this->original_tags[$tag->get_id()] = 1;
     } else {
         if (!isset($this->tags[$tag])) {
             $new_tag = new HighriseTag();
             $new_tag->set_name($tag);
             $this->tags[$tag] = $new_tag;
         }
     }
 }