Examples with Comparators org.apache.druid.java.util.common.guava.Comparators used on opensource projects

Example 1 with Comparators

use of org.apache.druid.java.util.common.guava.Comparators in project druid by druid-io.

the class GroupByQuery method getRowOrderingForPushDown.

/**
 * When limit push down is applied, the partial results would be sorted by the ordering specified by the
 * limit/order spec (unlike non-push down case where the results always use the default natural ascending order),
 * so when merging these partial result streams, the merge needs to use the same ordering to get correct results.
 */
private Ordering<ResultRow> getRowOrderingForPushDown(final boolean granular, final DefaultLimitSpec limitSpec) {
    final boolean sortByDimsFirst = getContextSortByDimsFirst();
    final IntList orderedFieldNumbers = new IntArrayList();
    final Set<Integer> dimsInOrderBy = new HashSet<>();
    final List<Boolean> needsReverseList = new ArrayList<>();
    final List<ColumnType> dimensionTypes = new ArrayList<>();
    final List<StringComparator> comparators = new ArrayList<>();
    for (OrderByColumnSpec orderSpec : limitSpec.getColumns()) {
        boolean needsReverse = orderSpec.getDirection() != OrderByColumnSpec.Direction.ASCENDING;
        int dimIndex = OrderByColumnSpec.getDimIndexForOrderBy(orderSpec, dimensions);
        if (dimIndex >= 0) {
            DimensionSpec dim = dimensions.get(dimIndex);
            orderedFieldNumbers.add(resultRowSignature.indexOf(dim.getOutputName()));
            dimsInOrderBy.add(dimIndex);
            needsReverseList.add(needsReverse);
            final ColumnType type = dimensions.get(dimIndex).getOutputType();
            dimensionTypes.add(type);
            comparators.add(orderSpec.getDimensionComparator());
        }
    }
    for (int i = 0; i < dimensions.size(); i++) {
        if (!dimsInOrderBy.contains(i)) {
            orderedFieldNumbers.add(resultRowSignature.indexOf(dimensions.get(i).getOutputName()));
            needsReverseList.add(false);
            final ColumnType type = dimensions.get(i).getOutputType();
            dimensionTypes.add(type);
            comparators.add(StringComparators.LEXICOGRAPHIC);
        }
    }
    final Comparator<ResultRow> timeComparator = getTimeComparator(granular);
    if (timeComparator == null) {
        return Ordering.from((lhs, rhs) -> compareDimsForLimitPushDown(orderedFieldNumbers, needsReverseList, dimensionTypes, comparators, lhs, rhs));
    } else if (sortByDimsFirst) {
        return Ordering.from((lhs, rhs) -> {
            final int cmp = compareDimsForLimitPushDown(orderedFieldNumbers, needsReverseList, dimensionTypes, comparators, lhs, rhs);
            if (cmp != 0) {
                return cmp;
            }
            return timeComparator.compare(lhs, rhs);
        });
    } else {
        return Ordering.from((lhs, rhs) -> {
            final int timeCompare = timeComparator.compare(lhs, rhs);
            if (timeCompare != 0) {
                return timeCompare;
            }
            return compareDimsForLimitPushDown(orderedFieldNumbers, needsReverseList, dimensionTypes, comparators, lhs, rhs);
        });
    }
}