public SimpleNode[] getSelectedNodesIfUniform() {
    List<SimpleNode> result = new ArrayList<>();
    TreePath[] selectionPaths = getSelectionPaths();
    if (selectionPaths != null) {
      SimpleNode lastNode = null;
      for (TreePath selectionPath : selectionPaths) {
        SimpleNode nodeFor = getNodeFor(selectionPath);

        if (lastNode != null && lastNode.getClass() != nodeFor.getClass()) {
          return new SimpleNode[0];
        }

        result.add(nodeFor);
        lastNode = nodeFor;
      }
    }
    return result.toArray(new SimpleNode[0]);
  }
public SimpleNode[] getSelectedNodesIfUniform()