I am trying to understand two sequence diagrams that I have found in the SE course at university of Washington. Can you confirm if my understanding is correct ?
According to my understanding , this sequence diagram describes the dispatch process of orders to either of two distributors. First of all, there will be a dispatch message for certain order (object of order class). After that for each item in this order (loop) , for if the value of this item is more than 1000 we will make the careful distributor (certain object of distributor class) to dispatch this order. In other words , we will send a message or call the dispatch function of the careful object of the distributor class. Else , if the value is less than 1000 , the other distributor "regular" will dispatch this item.
I understand that this diagram describes the operation of buying some items from certain storefront. For certain storefront ( object of storefront class , say amazon ) , there will be a loop for each item or stock available at this storefront, every item will be added to a certain object of cart class and this cart object will call a certain inventory object to reserve this item (call reservethisitem method of that belongs to this object). Next , this inventory object will acknowledge the cart object and the cart object will acknowledge the storefront object for adding this item. After that ,the storefront object will send a message for the cart object to make the checkout of these items that are added to the cart from the for loop. Next , this cart object will invoke its processorder function to process the order. Next this "self function " will invoke the confirmOrder method of the storefront object. Next , the storefront will acknowledge this message , meaning that the order has been confirmed and then an acknowledgment will be sent by the cart order to acknowledge the checkout process. Finally , the cart object will invoke the placeItemInOrder function of the inventory object to place the checked out items in order.
Please someone correct me if there is any misunderstanding. Thanks