Question

A hotel keeps records of its sales in a text file (called "hotel.txt"). Each line contains the following information separated by semicolons (":"): The client's name, the service sold (such as Dining, Conference, ...), and the amount of the sale. The figure below shows a few lines of input file. Write a Java program that reads such a file to display some information on the Hotel. You are requested to use lambda expression and streams to display the following information 1. The total amount of sales 2. The count of sales > 100 3. The average amount for each service category sorted in ascending ordered by the average, 4. Display all the customers 5. All the services of a given customer sorted in descending order by the total amount of their sales. If two amounts are equal, then use the service name as tiebreaker (Hint: If needed, you can use the Pair class - see the appendix) Enter a customer: Zalaya Benjamin Bayer:Dining:26.5 Zalaya Lodging: 120.14 Zalaya:Lodging: 173.6 Chung-cha kim Conference:425 Zalaya:Dining:11.1 Service Total **************** Dining 11.4 Lodging 293.74 Figure 1. Sample Input file Figure 2. Sample run of (5)

Answer 1

import java.text.NumberFormat;

import java.util.ArrayList;

public class TallySales {

public static void main(String[] args) {

ArrayList<Sale> sales = new ArrayList<>();

NumberFormat currency = NumberFormat.getCurrencyInstance();

fillTheList(sales);

double total = sales.stream()

.filter((sale) -> sale.getItem().equals("hotel.txt"))

.map((sale) -> sale.getPrice())

.reduce(0.0, (price1, price2) -> price1 + price2);

System.out.println(currency.format(total));

}

static void fillTheList(ArrayList<Sale> sales) {

sales.add(new Sale("Dining", 11.1));

sales.add(new Sale("Dinning", 26.00));

sales.add(new Sale("lodging ", 173.6));

sales.add(new Sale("lodging",120.14 ));

}

}