class Tree extends Composite implements HasSelectionHandlers<T>,
                                                                   HasOpenHandlers<T>,
                                                                   HasCloseHandlers<T> {

    public T getItem(int index) {
        T item = null;
        Iterator<T> itemIter = getItems().iterator();
        int idx = 0;
        while (itemIter.hasNext()) {
            T treeItem = itemIter.next();
            if (idx == index) {
                item = treeItem;
                break;
            }
            idx++;
        }
        return item;
    }

    public  Tree();
      Tree(final Supplier<FlowPanel> containerProvider);

}