public boolean isSourceWidget(Widget arg0) {
   if (caratteristiche.getExpressionFunction() == null
       || caratteristiche.getExpressionFunction().equals("")) {
     return false;
   }
   return true;
 }
 // giannisk
 private void deleteTargetConnection(Widget sourceWidget) {
   ReviewCorrespondences review = new ReviewCorrespondences();
   review.removeCorrespondence(caratteristiche.getValueCorrespondence());
   caratteristiche.setTargetWidget(null);
   ConnectionWidget connection = new ConnectionWidget(sourceWidget.getScene());
   connection.removeFromParent();
   StatusDisplayer.getDefault()
       .setStatusText(NbBundle.getMessage(Costanti.class, Costanti.DELETE_CONNECTION));
 }
  public void createConnection(Widget sourceWidget, Widget targetWidget) {
    try {
      ConnectionWidget connection = new ConnectionWidget(sourceWidget.getScene());
      connection.setTargetAnchorShape(AnchorShape.TRIANGLE_FILLED);
      connection.setSourceAnchor(AnchorFactory.createRectangularAnchor(sourceWidget));
      connection.setTargetAnchor(AnchorFactory.createRectangularAnchor(targetWidget));
      Stroke stroke = Costanti.BASIC_STROKE;
      connection.setStroke(stroke);
      connection
          .getActions()
          .addAction(
              ActionFactory.createPopupMenuAction(
                  new MyPopupProviderConnectionFunc(
                      sourceWidget.getScene(), mainLayer, caratteristiche)));
      ConnectionInfo connectionInfo = new ConnectionInfo();
      connectionInfo.setTargetWidget(targetWidget);
      connectionInfo.setConnectionWidget(connection);
      caratteristiche.setTargetWidget((VMDPinWidgetTarget) targetWidget);

      creator.createCorrespondenceWithFunction(
          mainLayer, targetWidget, caratteristiche, connectionInfo);

      caratteristiche.setConnectionInfo(connectionInfo);
      connectionLayer.addChild(connection, connectionInfo);
    } catch (ExpressionSyntaxException e) {
      DialogDisplayer.getDefault()
          .notify(
              new NotifyDescriptor.Message(
                  NbBundle.getMessage(Costanti.class, Costanti.SYNTAX_WARNING)
                      + " : "
                      + e.getMessage(),
                  DialogDescriptor.WARNING_MESSAGE));
      // giannisk delete target connection if exception if caught
      deleteTargetConnection(sourceWidget);
    }
  }