in service/src/main/java/org/apache/fineract/cn/group/rest/GroupRestController.java [293:299]
private Pageable createPageRequest(final Integer page, final Integer size, final String sortColumn, final String sortDirection) {
final Integer pageToUse = page != null ? page : 0;
final Integer sizeToUse = size != null ? size : 20;
final String sortColumnToUse = sortColumn != null ? sortColumn : "identifier";
final Sort.Direction direction = sortDirection != null ? Sort.Direction.valueOf(sortDirection.toUpperCase()) : Sort.Direction.ASC;
return new PageRequest(pageToUse, sizeToUse, direction, sortColumnToUse);
}