code: private NodeData getACL(String identifier, ACLSearch search) throws RepositoryException
     {
        final ItemData item = getItemData(identifier, false);
        return item != null && item.isNode() ? initACL(null, (NodeData)item, search) : null;
     }
docs: Find Item by identifier to get the missing ACL information.
  
  @param identifier the id of the node that we are looking for to fill the ACL research
  @param search the ACL search describing what we are looking for
  @return NodeData, data by identifier