code: private void processCustomIdNodeMapping(final Map<String, TreeItemIdNode> map, final TreeItemIdNode node) {
  		String itemId = node.getItemId();
  		if (!Util.empty(itemId)) {
  			map.put(itemId, node);
  		}
  
  		for (TreeItemIdNode childItem : node.getChildren()) {
  			processCustomIdNodeMapping(map, childItem);
  		}
  	}
docs: Iterate over the custom tree structure to add entries to the map.
  
  @param map the map of custom items and their node
  @param node the current node being processed