private JSONObject saveModelNodes(List<Model> nodesToSave) throws JSONException { JSONArray errorNodes = new JSONArray(); JSONObject respObj = new JSONObject(); // loop over nodes and order them ascending TreeMap<Integer, Model> treeMap = new TreeMap<Integer, Model>(); for (int i = 0; i < nodesToSave.size(); i++) { Model model = (Model) nodesToSave.get(i); // loads all nodes guiid with type error respObj.put(model.getGuiId(), "OK"); respObj.put("label", model.getLabel()); if (model.getParentId() != null) { // look up for its id: if null --> newly created node Integer id = model.getId(); if (id == null) { treeMap.put(Integer.valueOf("-" + i + 1), model); } else { // else to modify node treeMap.put(model.getId(), model); } } else { // root node --> save first try { if (model.getId() != null) { modelDao.modifyModel(model); respObj.put(model.getGuiId(), model.getId()); respObj.put(model.getId() + "", model.getLabel()); } else { Integer index = modelDao.insertModel(model); respObj.put(model.getGuiId(), index); respObj.put(index + "", model.getLabel()); } } catch (Exception e) { // send error!!! respObj.put(model.getGuiId(), "KO"); } } } Set set = treeMap.entrySet(); // Get an iterator Iterator it = set.iterator(); // loop again over treemap while (it.hasNext()) { Map.Entry orderedEntry = (Map.Entry) it.next(); // check that parent exists Model orderedNode = (Model) orderedEntry.getValue(); // GET JSON OBJECT VALUE Integer parentId = orderedNode.getParentId(); try { Model parent = modelDao.loadModelWithoutChildrenById(parentId); if (parent != null) { // if parent exists--> save // if node id is negative --> insert if (orderedNode.getId() == null) { Integer newId = modelDao.insertModel(orderedNode); if (newId != null) { orderedNode.setId(newId); respObj.put(orderedNode.getGuiId(), newId); respObj.put(newId + "", orderedNode.getLabel()); } else { respObj.put(orderedNode.getGuiId(), "KO"); } } else { // else update modelDao.modifyModel(orderedNode); respObj.put(orderedNode.getGuiId(), orderedNode.getId()); respObj.put(orderedNode.getId() + "", orderedNode.getLabel()); } } } catch (Exception e) { // if parentId != null but no parent node stored on db --> exception respObj.put(orderedNode.getGuiId(), "KO"); } } return respObj; }