Examples with DESCENDING org.apache.calcite.rel.RelFieldCollation.Direction.DESCENDING used on opensource projects

Example 1 with DESCENDING

use of org.apache.calcite.rel.RelFieldCollation.Direction.DESCENDING in project hazelcast by hazelcast.

the class IndexResolver method buildCollationTrait.

/**
 * Builds a collation with collation fields re-mapped according to the table projections.
 *
 * @param scan  the logical map scan
 * @param index the index
 * @param ascs  the collation of index fields
 * @return the new collation trait
 */
private static RelCollation buildCollationTrait(FullScanLogicalRel scan, MapTableIndex index, List<Boolean> ascs) {
    if (index.getType() != SORTED) {
        return RelCollations.of(Collections.emptyList());
    }
    List<RelFieldCollation> fields = new ArrayList<>(index.getFieldOrdinals().size());
    HazelcastTable table = OptUtils.extractHazelcastTable(scan);
    // Extract those projections that are direct input field references. Only those can be used
    // for index access
    List<Integer> fieldProjects = table.getProjects().stream().filter(expr -> expr instanceof RexInputRef).map(inputRef -> ((RexInputRef) inputRef).getIndex()).collect(Collectors.toList());
    for (int i = 0; i < index.getFieldOrdinals().size(); ++i) {
        Integer indexFieldOrdinal = index.getFieldOrdinals().get(i);
        int remappedIndexFieldOrdinal = fieldProjects.indexOf(indexFieldOrdinal);
        if (remappedIndexFieldOrdinal == -1) {
            // The field is not used in the query
            break;
        }
        Direction direction = ascs.get(i) ? ASCENDING : DESCENDING;
        RelFieldCollation fieldCollation = new RelFieldCollation(remappedIndexFieldOrdinal, direction);
        fields.add(fieldCollation);
    }
    return RelCollations.of(fields);
}