// Retrieve the purchaseOrder
Optional<PurchaseOrder> purchaseOrder = purchaseOrderReadService.getById(purchaseOrderId);
ResourceAsserts.assertPresent(purchaseOrder,"purchaseOrder");
// Verify and apply any changes to the PurchaseOrder
PurchaseOrder persistentPurchaseOrder = purchaseOrder.get();
apply(updatePurchaseOrderRequest,persistentPurchaseOrder);
// Persist the updated purchaseOrder
persistentPurchaseOrder = purchaseOrderReadService.saveOrUpdate(persistentPurchaseOrder);