Data-Centric Applications with Vaadin 8

Enabling ordering in the UI

As we have previously discussed, the DataProvider interface uses an object of type List<QuerySortOrder> to provide the ordering configuration. However, the backend service requires an object of type Map<String, Boolean>. We have to implement a helper method that translates between these two types. We can add this method to a separate DataUtils class and implement it as follows:

public class DataUtils {    public static <T, F> Map<String, Boolean> getOrderMap(            Query<T, F> query) {        Map<String, Boolean> map = new LinkedHashMap<>();        for (QuerySortOrder order : query.getSortOrders()) {            String property = order.getSorted();            boolean isAscending = SortDirection.ASCENDING.equals(                    order.getDirection());            map.put(property, isAscending) ...