List<CriterionTreeNode> rootList = new ArrayList<CriterionTreeNode>();
for (Entry<CriterionType, Set<Criterion>> entry : criterions.entrySet()) {
rootList.add(asNode(entry.getKey(), entry.getValue()));
}
CriterionTreeNode root = new CriterionTreeNode("Root", rootList);
return new SimpleTreeModel(root);
}