/**
* Apply sorting to the current ListDataSource.
*
* @param order the sort order list provided by the grid sort event
*/
private void sort(final List<SortOrder> order) {
DataSource<T> ds = grid.getDataSource();
if (!(ds instanceof ListDataSource)) {
throw new IllegalStateException("Grid " + grid + " data source is not a ListDataSource!");
}
((ListDataSource<T>) ds)
.sort(
new Comparator<T>() {
@Override
@SuppressWarnings({"rawtypes", "unchecked"})
public int compare(T a, T b) {
for (SortOrder o : order) {
Grid.Column column = o.getColumn();
Comparator cmp = ListSorter.this.comparators.get(column);
int result = 0;
Object value_a = column.getValue(a);
Object value_b = column.getValue(b);
if (cmp != null) {
result = cmp.compare(value_a, value_b);
} else {
if (!(value_a instanceof Comparable)) {
throw new IllegalStateException(
"Column "
+ column
+ " has no assigned comparator and value "
+ value_a
+ " isn't naturally comparable");
}
result = ((Comparable) value_a).compareTo(value_b);
}
if (result != 0) {
return o.getDirection() == SortDirection.ASCENDING ? result : -result;
}
}
if (order.size() > 0) {
return order.get(0).getDirection() == SortDirection.ASCENDING
? a.hashCode() - b.hashCode()
: b.hashCode() - a.hashCode();
}
return a.hashCode() - b.hashCode();
}
});
}
public ListSorter(Grid<T> grid) {
if (grid == null) {
throw new IllegalArgumentException("Grid can not be null");
}
this.grid = grid;
comparators = new HashMap<>();
sortHandlerRegistration =
grid.addSortHandler(
new SortHandler<T>() {
@Override
public void sort(SortEvent<T> event) {
ListSorter.this.sort(event.getOrder());
}
});
}