cell values not updating

TableColumn<CollapsingVarData, String> ruleCategoryCol= new TableColumn<CollapsingVarData, String>(strColName);
        ruleCategoryCol.setCellValueFactory(new Callback<CellDataFeatures<CollapsingVarData, String>, ObservableValue<String>>() {

            @Override
            public ObservableValue<String> call(CellDataFeatures<CollapsingVarData, String> arg0) {
                return arg0.getValue().collapseRule();
            }
        });

        Callback<TableColumn<CollapsingVarData, String>, TableCell<CollapsingVarData, String>> ruleCellFactory =
                            new Callback<TableColumn<CollapsingVarData, String>, TableCell<CollapsingVarData, String>>() {

            @Override
            public TableCell<CollapsingVarData, String> call(TableColumn<CollapsingVarData, String> arg0) {
                TableCell<CollapsingVarData, String> cell  = new TableCell<CollapsingVarData, String>(){
                    @Override
                    public void updateItem(String strVal, boolean empty)
                    {
                        ChoiceBox<String> valuesRuleBox = new ChoiceBox();
                        valuesRuleBox.getItems().addAll("Character", "Categorical", "Numeric");
                        valuesRuleBox.getSelectionModel().selectFirst();
                        setGraphic(valuesRuleBox);
                    }
                };

                //cell.setgr
                cell.setEditable(true);
                return cell;
            }
        };
        ruleCategoryCol.setCellFactory(ruleCellFactory);