     import weave.data.AttributeColumns.ProxyColumn;
     import weave.data.AttributeColumns.StringColumn;
     import weave.data.QKeyManager;
+    import weave.data.hierarchy.ColumnTreeNode;
     import weave.utils.VectorUtils;
 
     public class GraphMLDataSource extends AbstractDataSource


        override public function getHierarchyRoot():IWeaveTreeNode
        {
            if (!(_rootNode is GraphMLGraphNode))
            {
                _rootNode = new GraphMLGraphNode(this);
            }

            return _rootNode;


        override protected function generateHierarchyNode(metadata:Object):IWeaveTreeNode
        {
            return new ColumnTreeNode({
                source: this,
                idFields: [GRAPH_GROUP_META, GRAPH_ID_META],
                columnMetadata: metadata
            });
        }

        private function handleURLChange():void
