问多重ColumnSorting与AsyncDataProvider

EN

    AsyncHandler handler = new AsyncHandler(myGridTable);
    myGridTable.addColumnSortHandler(handler);
    myGridTable.getColumnSortList().push(A_column);
    myGridTable.getColumnSortList().push(B_column);

    AsyncDataProvider<AdminModel> provider = new AsyncDataProvider<AdminModel>() {
        protected void onRangeChanged(final HasData<AdminModel> display) {
            final int start = display.getVisibleRange().getStart();
            int length = display.getVisibleRange().getLength();

            AsyncCallback<String> callback = new AsyncCallback<String> {
                public void onFailure(final Throwable caught) {
                    Window.alert(caught.getMessage());
                }
                public void onSuccess(final String result) {
                    ........
                    updateRowData(start, adminList);
                }
            };
            final ColumnSortList sortList = myGridTable.getColumnSortList();
            // Here to determine which column sort

            // send request to server
        }
    };

    provider.addDataDisplay(view.getDataGridResults());