Question

Program Requirements:

This assignment requires you to create one program in Java to simulate a Point-of-Sale (POS) system. The solution must be in JAVA language.
You create the main program called POSmain.java and two classes: ShoppingCart and CashRegister.
Your POSmain program should take three file names from command line arguments. The first file contains a list of products and their prices; the second and third files are lists of items in two shopping carts of two customers. The POSmain program should first read the price file, then read each of the cart files to load a list of items in a shopping cart and store them in a ShoppingCart objects. The price file may contain a variable number of products and the cart files may contain a variable number of items.
POSmain then will create a CashRegister object by passing the price list to it. The POSmain program then will use the CashRegister object to scan items in a cart and print a receipt for each shopping cart one by one. At last, POSmain will use the CashRegister object to print a report for the day.
The students will the report for the day, which requires design of your CashRegister class.

cart1.txt:

TV          
Table
Table   
Bed
Bed
Chair
Chair
Chair
Chair    

cart2.txt:

Milk  
Butter  
Tomato
Tomato
Tomato
Tomato
Tomato
Onion
Onion
Onion
Lettuce
Milk  
Ham  
Bread
Bread

price.txt:

TV           999.99
Table 199
Bed 499.99
Chair 45.49
Milk   3.00
Butter   2.84
Tomato 0.76
Onion 0.54
Lettuce 1.00
Ham   2.50
Bread 1.75

Program Output:
One customer is checking out ...
========================================
Product Price Qty Subtotal
----------------------------------------
Bed $499.99 2 $999.98
Char $45.49 4 $181.96
TV $999.99 1 $999.99
Table $199.0 2 $398.0
-------------------------
Total $2579.93
========================================
One customer is checking out ...
========================================
Product Price Qty Subtotal
----------------------------------------
Bread $1.75 2 $3.5
Butter $2.84 1 $2.84
Ham $2.5 1 $2.5
Lettuce $1.0 1 $1.0
Milk $3.0 2 $6.0
Onions $0.54 3 $1.62
Tomato $0.76 5 $3.8
-------------------------
Total $21.26
========================================
Report for the day
========================================
Number of customers: 2
Total sale: $2601.19
List of products sold:
----------------------------------------
Product Qty
----------------------------------------
Bed 2
Bread 2
Butter 1
Char 4
Ham 1
Lettuce 1
Milk 2
Onions 3
TV 1
Table 2
Tomato 5

Answer 1

NOTE:-
-> Your txt Files has two many spaces after prices and Item Names, So I removed before using, You should do same or Use txt Files I am providing in End

-> I am putting Files in C:// to avoid path errors, You Should Do Same or Change path POSmain.java line 31, 40, 47
Path pricePath = Paths.get("C:\\" + priceFile + ".txt");

-> I am taking only file name as input, don't enter .txt

RESULT:

CODE: (Also Including text code in end)
POSmain.java

ShoppingCart.java

CashRegister.java

CODE:
POSmain.java

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.HashMap;
import java.util.Scanner;
import java.util.stream.Stream;

public class POSmain {

    // Variables
    private static Scanner scanner;
    private static ShoppingCart cart1;
    private static ShoppingCart cart2;
    private static HashMap<String, Double> priceMap;

    public static void main(String[] args) throws IOException {

        // Initializing Variables
        scanner = new Scanner(System.in);
        ShoppingCart cart1 = new ShoppingCart();
        ShoppingCart cart2 = new ShoppingCart();
        priceMap = new HashMap<>();

        //Reading Files
        print("***POS Program***");
        while (true) {
            try {
                print("Input Price File Name:");
                String priceFile = input();
                Path pricePath = Paths.get("C:\\" + priceFile + ".txt");
                //Reading File
                Stream<String> lines = Files.lines(pricePath);
                //Saving Price Data
                lines.forEach(s -> savePrice(s));

                //Saving Cart 1 Items
                print("Input 1st Customer's Cart File Name:");
                String cart1File = input();
                Path cart1Path = Paths.get("C:\\" + cart1File + ".txt");
                Stream<String> lines2 = Files.lines(cart1Path);
                lines2.forEach(s -> cart1.addItem(s));

                //Saving Cart 2 Items
                print("Input 2nd Customer's Cart File Name:");
                String cart2File = input();
                Path cart2Path = Paths.get("C:\\" + cart2File + ".txt");
                Stream<String> lines3 = Files.lines(cart2Path);
                lines3.forEach(s -> cart2.addItem(s));
                break;
            } catch (Exception e) {
                print("Error: File Not Found" + e.getMessage());
            }
        }

        // Sell Items
        CashRegister cashRegister = new CashRegister(priceMap);
        cashRegister.sellItems(cart1);
        cashRegister.sellItems(cart2);
        cashRegister.printReportOfDay();
    }

    private static void savePrice(String data) {
        String[] splited = data.split("\\s+");
        priceMap.put(splited[0], Double.parseDouble(splited[1]));
    }

    private static String input() {
        return scanner.nextLine();
    }

    private static void print(String s) {
        System.out.println(s);
    }

}

ShoppingCart.java

import java.util.ArrayList;

public class ShoppingCart {

    private ArrayList<String> items;
  
    public ShoppingCart() {
        items = new ArrayList<>();
    }
  
    public void addItem(String item) {
        items.add(item);
    }
  
    public ArrayList<String> getItems() {
        return items;
    }
  
}

CashRegister.java

import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Set;

public class CashRegister {

    private HashMap<String, Double> priceMap;
    private int customerCount;
    private double totalSale;
    private HashMap<String, Integer> productsSold;
    // For Priniting Line
    public String line = new String(new char[48]).replace('\0', '-');
    public String doubleLine = new String(new char[48]).replace('\0', '=');
    private DecimalFormat df = new DecimalFormat("#.##");

    public CashRegister(HashMap<String, Double> prices) {
        priceMap = prices;
        customerCount = 0;
        totalSale = 0;
        productsSold = new HashMap<>();
    }

    public void sellItems(ShoppingCart cart) {
        print("One Customer is Checking Out...");
        print(doubleLine);
        print("Product Price Qty SubTotal");
        print(line);

        double total = 0;
        ArrayList<String> purchaseItems = cart.getItems();
        ArrayList<String> uniqueItems = new ArrayList<>();

        // Finding Unique Items In Card
        Set<String> set = new HashSet<>(purchaseItems);
        uniqueItems.addAll(set);

        for (String item : uniqueItems) {
            double price = priceMap.get(item);
            int qty = Collections.frequency(purchaseItems, item);
            double subTotal = price * qty;
            print(item + " $" + price + " " + qty + " $" + subTotal);
            total += subTotal;

            //Update Register
            totalSale += subTotal;
            if (productsSold.containsKey(item)) {
                productsSold.put(item, productsSold.get(item) + qty);
            } else {
                productsSold.put(item, qty);
            }

        }
        print(line);
        print("Total $" + df.format(total));
        print(doubleLine);
        customerCount++;
    }

    public void printReportOfDay() {
        print(doubleLine);
        print("Report for the day");
        print(doubleLine);
        print("Number of Customers: " + customerCount);
        print("Total Sale: $" + df.format(totalSale));
        print("List of products sold:");
        print(line);
        print("Product Qty");
        print(line);
        for (String key : productsSold.keySet()) {
            print(key + " " + productsSold.get(key));
        }

    }

    private void print(String s) {
        System.out.println(s);
    }

}

price.txt

TV 999.99
Table 199
Bed 499.99
Chair 45.49
Milk 3.00
Butter 2.84
Tomato 0.76
Onion 0.54
Lettuce 1.00
Ham 2.50
Bread 1.75

cart1.txt

TV
Table
Table
Bed
Bed
Chair
Chair
Chair
Chair

cart2.txt

Milk
Butter
Tomato
Tomato
Tomato
Tomato
Tomato
Onion
Onion
Onion
Lettuce
Milk
Ham
Bread
Bread