public double getParentAngle(final TreeNode<ChartData> NODE) {
        List<TreeNode<ChartData>> parentList = new ArrayList<>();
        TreeNode<ChartData> node = NODE;
        while (!node.getParent().isRoot()) {
            node = node.getParent();
            parentList.add(node);
        }
        Collections.reverse(parentList);
        double parentAngle = 360.0;
        for (TreeNode<ChartData> n : parentList) { parentAngle = parentAngle * getPercentage(n); }
        return parentAngle;
    }
Defines the root element of the tree
@param TREE
src/main/java/eu/hansolo/tilesfx/chart/SunburstChart.java