saveRecursive example

$children[$link['parent']][$id] = $id;
        }
        else {
          // A top level link - we need them to root our tree.           $top_links[$id] = $id;
          $link['parent'] = '';
        }
        $links[$id] = $link;
      }
    }
    foreach ($top_links as $id) {
      $this->saveRecursive($id, $children, $links);
    }
    // Handle any children we didn't find starting from top-level links.     foreach ($children as $orphan_links) {
      foreach ($orphan_links as $id) {
        // Check for a parent that is not loaded above since only internal links         // are loaded above.         $parent = $this->loadFull($links[$id]['parent']);
        // If there is a parent add it to the links to be used in         // ::saveRecursive().         if ($parent) {
          $links[$links[$id]['parent']] = $parent;
        }