package org.hso.ecommerce.supplier.data; import java.util.HashMap; public class DeliveryManager { private HashMap deliveryList; private static DeliveryManager deliveryManager; private DeliveryManager() { deliveryList = new HashMap<>(); } public static DeliveryManager getInstance() { if (DeliveryManager.deliveryManager == null) { DeliveryManager.deliveryManager = new DeliveryManager(); } return DeliveryManager.deliveryManager; } public void add(Delivery delivery) { deliveryList.put(delivery.getUuid(), delivery); } public Delivery getDeliveryByID(String uuid) { return deliveryList.getOrDefault(uuid, null); } }