@Override
 public Displayer lookupDisplayer(DisplayerSettings displayerSettings) {
   DisplayerType type = displayerSettings.getType();
   if (BARCHART.equals(type)) return new LienzoBarChartDisplayer();
   if (PIECHART.equals(type)) return new LienzoPieChartDisplayer();
   if (LINECHART.equals(type)) return new LienzoLineChartDisplayer();
   return null;
 }
 public <D extends AbstractDisplayer> D initDisplayer(D displayer, DisplayerSettings settings) {
   displayer.setEvaluator(new DisplayerEvaluatorMock());
   displayer.setFormatter(new DisplayerFormatterMock());
   if (settings != null) {
     displayer.setDisplayerSettings(settings);
     displayer.setDataSetHandler(
         new DataSetHandlerImpl(clientServices, settings.getDataSetLookup()));
   }
   return displayer;
 }