private function sortPlanningsAccordinglyToHierarchy(array &$plannings) { if (!$plannings) { return; } $tracker_ids = array_map(array($this, 'getPlanningTrackerId'), $plannings); $hierarchy = $this->tracker_factory->getHierarchy($tracker_ids); $this->tmp_tracker_ids_to_sort_plannings = $hierarchy->sortTrackerIds($tracker_ids); usort($plannings, array($this, 'cmpPlanningTrackerIds')); }