Question

JAVA

Use the class, Invoice, provided to create an array of Invoice objects. Class Invoice includes four instance variables; partNumber (type String), partDescription (type String), quantity of the item being purchased (type int0, and pricePerItem (type double). Perform the following queries on the array of Invoice objects and display the results:

1. Use streams to sort the Invoice objects by partDescription, then display the results.

2. Use streams to sort the Invoice objects by pricePerItem, then display the results.

3. Use streams to map each Invoice to its partDescription and quantity, sort the

   results by quantity, then display the results

4. Use streams to map each Invoice to its partDescription and the value of the

   Invoice (i.e., quantity * pricePerItem). Order the results by Invoice value.

5. Modify Part (d) to select the Invoice values in the range $200.00 to $500.00.

6. Find any one Invoice in which the partDescription contains the word “saw”.

Use the data below to test your program.

Invoice Data

Part Number	Part Description	Quantity	Price
83	Electric sander	7	57.98
24	Power saw	18	99.99
7	Sledge hammer	11	21.50
77	Hammer	76	11.99
39	Lawn mower	3	79.50
68	Screwdriver	106	6.99
56	Jig saw	21	11.00
3	Wrench	34	7.50

//***************************************************************
//  Description:       Invoice class.  Do NOT modify this Class.
//***************************************************************

public class Invoice {
   private final int partNumber; 
   private final String partDescription;
   private int quantity;
   private double price;

   // constructor
   public Invoice(int partNumber, String partDescription, int quantity, double price)
   {
      if (quantity < 0) { // validate quantity
         throw new IllegalArgumentException("Quantity must be>= 0");
      }

      if (price < 0.0) { // validate price
         throw new IllegalArgumentException(
            "Price per item must be>= 0");
      }

      this.partNumber = partNumber;
      this.partDescription = partDescription;
      this.quantity = quantity;
      this.price = price;
   }

   // get part number
   public int getPartNumber() {
      return partNumber; // should validate
   } 

   // get description
   public String getPartDescription() {
      return partDescription;
   } 

   // set quantity
   public void setQuantity(int quantity) {
      if (quantity <0) { // validate quantity
         throw new IllegalArgumentException("Quantity must be>= 0");
      }

      this.quantity = quantity;
   } 

   // get quantity
   public int getQuantity() {
      return quantity;
   }

   // set price per item
   public void setPrice(double price) {
      if (price <0.0) { // validate price
         throw new IllegalArgumentException(
            "Price per item must be>= 0");
      }

      this.price = price;
   } 

   // get price per item
   public double getPrice() {
      return price;
   } 

   // return String representation of Invoice object
   @Override
   public String toString() {
      return String.format(
         "Part #: %-2d  Description: %-15s  Quantity: %-4d  Price: $%,6.2f", 
         getPartNumber(), getPartDescription(), 
         getQuantity(), getPrice());
   } 
}

Answer 1

Code Implemented in java:

Code comments are available for part implementation.

Filename: Invoice.java

public class Invoice {
    int PartNumber;
    String PartDescription;
    int Quantity;
    double Price;

    @Override
    public String toString() {
        return "Invoice{" + "PartNumber=" + PartNumber + ", PartDescription=" + PartDescription + ", Quantity=" + Quantity + ", Price=" + Price + '}';
    }

    public Invoice(int PartNumber, String PartDescription, int Quantity, double Price) {
        this.PartNumber = PartNumber;
        this.PartDescription = PartDescription;
        this.Quantity = Quantity;
        this.Price = Price;
    }

    public int getPartNumber() {
        return PartNumber;
    }

    public void setPartNumber(int PartNumber) {
        this.PartNumber = PartNumber;
    }

    public String getPartDescription() {
        return PartDescription;
    }

    public void setPartDescription(String PartDescription) {
        this.PartDescription = PartDescription;
    }

    public int getQuantity() {
        return Quantity;
    }

    public void setQuantity(int Quantity) {
        this.Quantity = Quantity;
    }

    public double getPrice() {
        return Price;
    }

    public void setPrice(double Price) {
        this.Price = Price;
    }

}

Filename: Main.java

import java.sql.*;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;

public class Main {
public static void main(String[] args) {
Object[] array = {
new Invoice(83, "Electric sander", 7, 57.98),
new Invoice(24, "Power saw", 18, 99.99),
new Invoice(7, "Sledge hammer", 11, 21.50),
new Invoice(77, "Hammer", 76, 11.99),
new Invoice(39, "Lawm nower", 3, 79.50),
new Invoice(68, "Screwdriver", 106, 6.99),
new Invoice(56, "Jig saw", 21, 11.00),
new Invoice(3, "Wrench", 34, 7.50)
};

try {
Class.forName("com.mysql.jdbc.Driver");
Connection connection = DriverManager.getConnection
("jdbc:mysql://localhost:3306/store_DB", "root", " ");
Statement statement = connection.createStatement();

//insert
PreparedStatement ps = connection.prepareStatement
("INSERT into invoice(fname,mname,lname) VALUES(?,?,?,?)");
for (Object obj : array) {
Invoice invoice = (Invoice) obj;
ps.setInt(1, invoice.getPartNumber());
ps.setString(2, invoice.getPartDescription());
ps.setInt(3, invoice.getQuantity());
ps.setDouble(4, invoice.getPrice());
ps.addBatch();
}

//select
ResultSet resultSet = statement.executeQuery("SELECT * from invoice");
List<Invoice> invoices = new ArrayList<>();
while (resultSet.next()) {
Invoice invoice = new Invoice(
resultSet.getInt("Part_Number"),
resultSet.getString("Part_Description"),
resultSet.getInt("Quantity"),
resultSet.getDouble("Price")
);
invoices.add(invoice);
}

//a (sort by PartDescription)
invoices.stream()
.sorted(Comparator.comparing(i -> i.getPartDescription()))
.forEach(s -> System.out.println(s));

//b (sort by Price)
invoices.stream()
.sorted(Comparator.comparing(i -> i.getPrice()))
.forEach(s -> System.out.println(s));

//c
invoices.stream()
.sorted(Comparator.comparing(i -> i.getQuantity()))
.map(i -> i.getPartDescription() + " " + i.getQuantity())
.forEach(s -> System.out.println(s));

//d
invoices.stream()
.sorted(Comparator.comparing(i -> i.getQuantity() * i.getPrice()))
.map(i -> i.getPartDescription() + " " + (i.getPrice() * i.getQuantity()))
.forEach(s -> System.out.println(s));

//e
invoices.stream()
.sorted(Comparator.comparing(i -> i.getQuantity() * i.getPrice()))
.filter(i-> (i.getQuantity() * i.getPrice()) >=200 && (i.getQuantity() * i.getPrice()) <=500 )
.map(i -> i.getPartDescription() + " " + (i.getPrice() * i.getQuantity()))
.forEach(s -> System.out.println(s));

} catch (ClassNotFoundException ex) {
System.err.println("Class Not Found!!!");
ex.printStackTrace();
} catch (SQLException ex) {
System.err.println("SQL Error!!!");
ex.printStackTrace();
}
}
}

If you like my answer, hit thumbs up.