code: public SecondaryTable<Entity<T>> getOrCreateSecondaryTable()
     {
        List<Node> nodeList = childNode.get("secondary-table");
        if (nodeList != null &&  nodeList.size() > 0)
        {
           return new SecondaryTableImpl<Entity<T>>(this, "secondary-table", childNode, nodeList.get(0));
        }
        return createSecondaryTable();
     }
docs: If not already created, a new <code>secondary-table</code> element will be created and returned.
  Otherwise, the first existing <code>secondary-table</code> element will be returned.
  @return the instance defined for the element <code>secondary-table</code>