Question

I have some .txt files, which I read in to build two objects.

Item, with fields:

Description|SKU|Retail Price|Discount

and Store with fields:

ID|Description|Street|City|Province|Postal Code|Store Phone|Auto Service

I have another .txt file for the Inventory object, which is a bridge entity which ties them together. Inventory’s fields are:

Store ID|Item SKU|Item Count

Obviously, those come from the Item and Store classes.

Here is my objective:

I want to create an inventory report which synthesizes the three lists into a single console printed output, but am hitting a wall about how to get there.

This is about as far as I got:

public static void write(List<Item> items, List<Store> stores, List<Stock> stocks) {
    System.out.println();
    System.out.println("Inventory Report");
    System.out.println("----------------");


    for (Item it : items) {
        for (Stock s : stocks) {
            if(it.getProductNumber() == s.getItemSKU()) {
                for (Store st: stores) {
                    if(st.getId() == s.getStoreID()) {
                        System.out.println(it.getDescription() + "is from store" + st.getId() + "in" + st.getCity()  + "and costs" + it.getPrice());
                    }
                }
            }
        }
    }
}

I know that the obvious solution should be creating tables and putting the info in, but this is an assignment that says that I should do it using pure java…

I am probably close, but my logic is off here… How best could one cross reference two Classes based on the third class?

Help would be much appreciated.

Answer 1

Store your Items and Stores in Maps, where their Id is the key:

    Map<Integer, Item> items = new HashMap<Integer, Item>();
    Map<Integer, Store> stores = new HashMap<Integer, Store>();

Pass them to your output method and it is easy as cake:

EDIT:Had little errors in the lines with a comment, fixed it.

public static void write(Map<Integer, Item> items, Map<Integer, Store> stores, List<Stock> stocks) {
    System.out.println();
    System.out.println("Inventory Report");
    System.out.println("----------------");

    for(Stock stock : stocks) { // <-- for all Stocks
        Store store = stores.get(stock.getStoreID()); // <-- get Store
        Item item = items.get(stock.getItemSKU());  // <-- get Item
        System.out.println(item.getDescription() + "is from store" + store.getId() + "in" + store.getCity()  + "and costs" + item.getPrice());
    }
}