Examples with OrderByExpression org.apache.phoenix.expression.OrderByExpression used on opensource projects

Example 6 with OrderByExpression

use of org.apache.phoenix.expression.OrderByExpression in project phoenix by apache.

the class OrderedResultIterator method buildComparator.

/**
 * Builds a comparator from the list of columns in ORDER BY clause.
 * @param orderByExpressions the columns in ORDER BY clause.
 * @return the comparator built from the list of columns in ORDER BY clause.
 */
// ImmutableBytesWritable.Comparator doesn't implement generics
@SuppressWarnings("unchecked")
private static Comparator<ResultEntry> buildComparator(List<OrderByExpression> orderByExpressions) {
    Ordering<ResultEntry> ordering = null;
    int pos = 0;
    for (OrderByExpression col : orderByExpressions) {
        Expression e = col.getExpression();
        Comparator<ImmutableBytesWritable> comparator = e.getSortOrder() == SortOrder.DESC && !e.getDataType().isFixedWidth() ? buildDescVarLengthComparator() : new ImmutableBytesWritable.Comparator();
        Ordering<ImmutableBytesWritable> o = Ordering.from(comparator);
        if (!col.isAscending())
            o = o.reverse();
        o = col.isNullsLast() ? o.nullsLast() : o.nullsFirst();
        Ordering<ResultEntry> entryOrdering = o.onResultOf(new NthKey(pos++));
        ordering = ordering == null ? entryOrdering : ordering.compound(entryOrdering);
    }
    return ordering;
}