private void addGroupsToNode(List<? extends FileGroup> groups, AbstractTreeNode owner, ActionInfo actionInfo) {
    for (FileGroup fileGroup : groups) {
      GroupTreeNode node = addFileGroup(fileGroup, owner, actionInfo);
      if (node != null) {
        addGroupsToNode(fileGroup.getChildren(), node, actionInfo);
      }
    }
  }
private void addGroupsToNode(List<? extends FileGroup> groups, AbstractTreeNode owner, ActionInfo actionInfo)