圣叹@游戏开发

public static function getUID(item:Object):String
{
  var result:String = null;
  
  if (item == null)
    return result;
  
  if (item is IUID)
  {
    result = IUID(item).uid;
    if (result == null || result.length == 0)
    {
      result = createUID();
      IUID(item).uid = result;
    }
  }
  else if ((item is IPropertyChangeNotifier) &&
    !(item is IUIComponent))
  {
    result = IPropertyChangeNotifier(item).uid;
    if (result == null || result.length == 0)
    {
      result = createUID();
      IPropertyChangeNotifier(item).uid = result;
    }
  }
  else if (item is String)
  {
    return item as String;
  }
  else
  {
    try
    {
      // We don't create uids for XMLLists, but if
      // there's only a single XML node, we'll extract it.
      if (item is XMLList && item.length == 1)
        item = item[0];
      
      if (item is XML)
      {
        // XML nodes carry their UID on the
        // function-that-is-a-hashtable they can carry around.
        // To decorate an XML node with a UID,
        // we need to first initialize it for notification.
        // There is a potential performance issue here,
        // since notification does have a cost,
        // but most use cases for needing a UID on an XML node also
        // require listening for change notifications on the node.
        var xitem:XML = XML(item);
        var nodeKind:String = xitem.nodeKind();
        if (nodeKind == "text" || nodeKind == "attribute")
          return xitem.toString();
        
        var notificationFunction:Function = xitem.notification();
        if (!(notificationFunction is Function))
        {
          // The xml node hasn't already been initialized
          // for notification, so do so now.
          notificationFunction =
            XMLNotifier.initializeXMLForNotification();
          xitem.setNotification(notificationFunction);
        }
        
        // Generate a new uid for the node if necessary.
        if (notificationFunction["uid"] == undefined)
          result = notificationFunction["uid"] = createUID();
        
        result = notificationFunction["uid"];
      }
      else
      {
        if ("mx_internal_uid" in item)
          return item.mx_internal_uid;
        
        if ("uid" in item)
          return item.uid;    
        
        result = uidDictionary[item];
        
        if (!result)
        {
          result = createUID();
          try
          {
            item.mx_internal_uid = result;
          }
          catch(e:Error)
          {
            uidDictionary[item] = result;
          }
        }
      }
    }
    catch(e:Error)
    {
      result = item.toString();
    }
  }
  
  return result;
}