@Override
public Comparator<Object> getComparator(
final PrestoContextRules rules, final PrestoField field, final Projection projection) {
if (projection != null && projection.isSorted() && field.isReferenceField()) {
return new FieldProjectionComparator(getPresto(), rules, field, projection);
} else {
return new FieldComparator(field, rules.isSortedAscendingField(field));
}
}
private FieldProjectionComparator(
Presto presto, PrestoContextRules rules, PrestoField field, Projection projection) {
this.presto = presto;
this.rules = rules;
this.field = field;
this.projection = projection;
boolean isAscending = rules.isSortedAscendingField(field);
String orderFieldId = null;
String orderBy = projection.getOrderBy();
if (orderBy != null) {
String[] split = orderBy.split(" ");
orderFieldId = split[0];
String orderDirection = split[1];
if (orderDirection != null) {
isAscending = !orderDirection.equals("desc");
}
}
this.ascending = isAscending;
this.orderField = orderFieldId;
}