// Example 5: sortDescendingHierarchically(Source joined, Source parent,
// boolean parentsFirst,
// boolean parentsRestrictedToBase)
// Select the descendants of a REGION value, which is the level above the
// WAREHOUSE level.
Source custSel = shipments.selectDescendants(
getExpressDataProvider()
.createConstantSource("SHIPMENTS_AW::REGION_AW::8"),
shipmentsParentAttr);
// Sort the selection hierarchically in descending order, with the parent
// values appearing after their children.