code: protected NodeImpl parent(final boolean pool) throws RepositoryException
     {
        NodeImpl parent = (NodeImpl)dataManager.getItemByIdentifier(getParentIdentifier(), pool);
        if (parent == null)
        {
           throw new ItemNotFoundException("FATAL: Parent is null for " + getPath() + " parent UUID: "
              + getParentIdentifier());
        }
        return parent;
     }
docs: Get parent node item.
  
  @param pool - take a parent from session pool
  @return parent item
  @throws RepositoryException if parent item is null