@Override
    public ExplorerTreeNode addChild(final ExplorerTreeNode parent,
                                     final ExplorerTreeNode child) {
        return addChildAt(parent, child, -1);
    }
Get the root node containing a particular node, or the node itself if it is a root node.
stroom-explorer/stroom-explorer-impl-db/src/main/java/stroom/explorer/impl/db/ExplorerTreeDaoImpl.java