Exercise 11-4 Inherit the Product class In this exercise, you’ll modify a versio

Question

Exercise 11-4   Inherit the Product class

In this exercise, you’ll modify a version of the Product application so it adds a class named MyProduct that extends the Product class and enhances its functionality.

Review the application

1.     Open the project named ch11_ex4_Product in the extra_ex_starts directory.

2.     Open the classes and review their code.

3.     Run the application to make sure it works correctly.

Create a new subclass and use it

4.     In the murach.business package, create a new class named MyProduct that inherits the Product class. This new class should add the following method to the Product class:

public String getPrice(NumberFormat nf)

This method should format the price for the product using the format that’s provided by the NumberFormat object that’s passed as a parameter.

5.     In the ProductDB class, modify the getProduct method so it returns a MyProduct object, not a Product object.

6.     In the ProductApp class, modify the code so it uses a MyProduct object, not a Product object. This should include using the getPrice method that’s only available from the MyProduct class to apply currency formatting to the price.

7.     Run the application to make sure that it still works correctly.

using Netbeans IDE

ProductDB class

package murach.db;

import murach.business.Product;

public class ProductDB {

public Product getProduct(String productCode) {
// In a more realistic application, this code would
// get the data for the product from a database
// For now, this code just uses if/else statements
// to return the correct product data

// create the Product object
Product product = new Product();

// fill the Product object with data
product.setCode(productCode);
if (productCode.equalsIgnoreCase("java")) {
product.setDescription("Murach's Java Programming");
product.setPrice(57.50);
} else if (productCode.equalsIgnoreCase("jsp")) {
product.setDescription("Murach's Java Servlets and JSP");
product.setPrice(57.50);
} else if (productCode.equalsIgnoreCase("mysql")) {
product.setDescription("Murach's MySQL");
product.setPrice(54.50);
} else {
product.setDescription("Unknown");
}
return product;
}
}

Product class

package murach.business;

import java.text.NumberFormat;

public class Product {

private String code;
private String description;
private double price;

public Product() {
code = "";
description = "";
price = 0;
}

public Product(String code, String description, double price) {
this.code = code;
this.description = description;
this.price = price;
}

public void setCode(String code) {
this.code = code;
}

public String getCode() {
return code;
}

public void setDescription(String description) {
this.description = description;
}

public String getDescription() {
return description;
}

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

public double getPrice() {
return price;
}
  
public String getPriceFormatted() {
NumberFormat currency = NumberFormat.getCurrencyInstance();
String priceFormatted = currency.format(price);
return priceFormatted;
}   
}

Product app class

package murach.ui;

import java.util.Scanner;
import murach.business.Product;
import murach.db.ProductDB;

public class ProductApp {

public static void main(String args[]) {
// display a welcome message
System.out.println("Welcome to the Product Viewer");
System.out.println();

// create 1 or more line items
Scanner sc = new Scanner(System.in);
String choice = "y";
while (choice.equalsIgnoreCase("y")) {
// get input from user
System.out.print("Enter product code: ");
String productCode = sc.nextLine();

// Use a ProductReader object to get the Product object
ProductDB db = new ProductDB();
Product product = db.getProduct(productCode);
  
// display the output
String message = " PRODUCT " +
"Code: " + product.getCode() + " " +
"Description: " + product.getDescription() + " " +
"Price: " + product.getPriceFormatted() + " ";
System.out.println(message);

// see if the user wants to continue
System.out.print("Continue? (y/n): ");
choice = sc.nextLine();
System.out.println();
}
System.out.println("Bye!");
}   
}

Explanation / Answer

Product.java

import java.text.NumberFormat;
public class Product {
private String code;
private String description;
private double price;
public Product() {
code = "";
description = "";
price = 0;
}
public Product(String code, String description, double price) {
this.code = code;
this.description = description;
this.price = price;
}
public void setCode(String code) {
this.code = code;
}
public String getCode() {
return code;
}
public void setDescription(String description) {
this.description = description;
}
public String getDescription() {
return description;
}
public void setPrice(double price) {
this.price = price;
}
public double getPrice() {
return price;
}
  
public String getPriceFormatted() {
NumberFormat currency = NumberFormat.getCurrencyInstance();
String priceFormatted = currency.format(price);
return priceFormatted;
}   
}

__________________

MyProduct.java

import java.text.NumberFormat;
import java.util.Locale;

public class MyProduct extends Product {
public String getPrice(NumberFormat nf) {
return nf.format(getPrice());
}
}

________________

ProductDB.java

public class ProductDB {
public MyProduct getProduct(String productCode) {
// In a more realistic application, this code would
// get the data for the product from a database
// For now, this code just uses if/else statements
// to return the correct product data
// create the Product object
MyProduct product = new MyProduct();
// fill the Product object with data
product.setCode(productCode);
if (productCode.equalsIgnoreCase("java")) {
product.setDescription("Murach's Java Programming");
product.setPrice(57.50);
} else if (productCode.equalsIgnoreCase("jsp")) {
product.setDescription("Murach's Java Servlets and JSP");
product.setPrice(57.50);
} else if (productCode.equalsIgnoreCase("mysql")) {
product.setDescription("Murach's MySQL");
product.setPrice(54.50);
} else {
product.setDescription("Unknown");
}
return product;
}
}

_________________

ProductApp.java

import java.text.NumberFormat;

import java.util.Locale;

import java.util.Scanner;

public class ProductApp {

public static void main(String args[]) {

// display a welcome message

System.out.println("Welcome to the Product Viewer");

System.out.println();

// create 1 or more line items

Scanner sc = new Scanner(System.in);

String choice = "y";

while (choice.equalsIgnoreCase("y")) {

// get input from user

System.out.print("Enter product code: ");

String productCode = sc.nextLine();

// Use a ProductReader object to get the Product object

ProductDB db = new ProductDB();

MyProduct product = db.getProduct(productCode);

//Locale locale = new Locale("en", "US");

Locale locale = Locale.getDefault();

NumberFormat nf=NumberFormat.getCurrencyInstance(locale);

// display the output

String message = " PRODUCT " +

"Code: " + product.getCode() + " " +

"Description: " + product.getDescription() + " " +

"Price: " + product.getPrice(nf) + " ";

System.out.println(message);

// see if the user wants to continue

System.out.print("Continue? (y/n): ");

choice = sc.nextLine();

System.out.println();

}

System.out.println("Bye!");

}   

}

__________________

Output:

Welcome to the Product Viewer

Enter product code: mysql

PRODUCT
Code: mysql
Description: Murach's MySQL
Price: $54.50

Continue? (y/n): y

Enter product code: java

PRODUCT
Code: java
Description: Murach's Java Programming
Price: $57.50

Continue? (y/n): y

Enter product code: jsp

PRODUCT
Code: jsp
Description: Murach's Java Servlets and JSP
Price: $57.50

Continue? (y/n): n

Bye!

_____________Could you rate me well.Plz .Thank You

Related Questions

Navigate

• Browse (All)
• Browse E
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.