FWD » Core Development » User Interface

While testing a medium-large GUI application I noticed that at some time (I was not able to pinpoint the exact trigger), a lot of messages like these get printed into console log:

WARNING: Unable to get the screen buffer for frame ID: 673. The frame with given ID is missing in widget registry.
Jun 28, 2017 1:15:14 PM com.goldencode.p2j.ui.chui.ThinClient getScreenBuffer

I did a short investigation and I see that on client side, WidgetRegistry.widgetList container does not reflect the widgets shown on the screen. Apparently there are some widgets that are not listed there, while a lot of other got left behind. Statistically, at some point, ~1500 widgets were stored, while only a a couple of tens were really on screen.
Of the grand total, about 660 were ScrollBarGuiButtons, 330 ScrollBarGuiImpl, 240 ButtonGuiImpl, 170 ScrollPaneGuiImpl. Other widgets I could spot in the list with less occurrences (<30): MenuItemGuiImpl, BrowseColumnGuiImpl.

Of course, the reason for the messages, if not the fact that the widgets don't get removed, it's exactly the reverse, but for the moment, I am thinking that these might be related.

A little help for the person who will further investigate this, I used the following piece of code for dumping WidgetRegistry.widgetList:

      if (debug)
      {
         Map<Class, Integer> map = new HashMap<>();
         for (Map.Entry<WidgetId, Widget<O>> wid : widgetList.entrySet())
         {
            Class<? extends Widget> c = wid.getValue().getClass();
            Integer cnt = map.get(c);
            if (cnt == null)
            {
               cnt = 1;
            }
            else
            {
               cnt = cnt + 1;
            }
            map.put(c, cnt);
         }
         System.out.println("WidgetRegistry.widgetList dump (" + widgetList.size() + " -> " + map.size() + ")");
         for (Map.Entry<Class, Integer> iter : map.entrySet())
         {
            System.out.println(iter.getKey() + "\t" + iter.getValue());
         }
         System.out.println("WidgetRegistry.widgetList dump ended.");
      }

As a side note, I think that for widgetList and generally, all places where WidgetId is used as key for a map, the indexing key used should be replaced with int/Integer. I think that the autoboxing of Java5 is a better solution than having to create temporary new WidgetId objects for accessing these maps.