Question

JAVA Programming ECLIPSE IDE

1.

Create an abstract class called Book. The class should declare the following variables:
an instance variable that describes the title - String
an instance variable that describes the ISBN - String
an instance variable that describes the publisher - String
an instance variable that describes the price - double
an instance variable that describes the year – integer

Provide a toString() method that returns the information stored in the above variables.

Create the getter and setter methods for each instance variable except price. Provide the necessary constructors. Include an abstract method setPrice(double price) to determine the price for a book. Include an abstract method getGenre() to return the genre of the book.

Create two subclasses called ScienceBook and ChildrenBook.

These subclasses should override the abstract methods setPrice and getGenre of class Book.

Use the following rule for setting the price for a book:
science books will have a 10% discount per each book
children books will have a fixed price (specified by user).

Write a driver program (another class with main method) that uses the above hierarchy. In your driver program you must implement an interaction with the user.
Use showInputDialog method to let the user input book information.
Use showMessageDialog method to display book information including price and type for both science and children books.

Answer 1

Book.java :

//Java class
public abstract class Book {
   //an instance variable that describes the title - String
   private String title;
   //an instance variable that describes the ISBN - String
   private String ISBN;
   //an instance variable that describes the publisher - String
   private String publisher;
   //an instance variable that describes the price - double
   private double price;
   //an instance variable that describes the year – integer
   private int year;
   //default constructor
   public Book()
   {
       this.title="";
       this.ISBN="";
       this.publisher="";
       this.price=0;
       this.year=0;
   }
   //getter and setter methods
   public String getTitle()
   {
       return this.title;
   }
   public void setTitle(String title)
   {
       this.title=title;
   }
   public String getISBN()
   {
       return this.ISBN;
   }
   public void setISBN(String isbn)
   {
       this.ISBN=isbn;
   }
   public String getPublisher()
   {
       return this.publisher;
   }
   public void setPublisher(String pub)
   {
       this.publisher=pub;
   }
   public int getYear()
   {
       return this.year;
   }
   public void setYear(int year)
   {
       this.year=year;
   }
   // an abstract method setPrice(double price) to determine the price for a book.
   public abstract void setPrice(double price);
   //abstract method getGenre() to return the genre of the book.
   public abstract String getGenre();
  
   // toString() method
   public String toString()
   {
       return "Title : "+this.title+"\nISBN : "+this.ISBN+"\nPublisher : "+this.publisher+"\nYear : "+this.year;
   }

}
*************************************************

ScienceBook.java :

//Java class with name ScienceBook that extends Book class
public class ScienceBook extends Book {
   private double price;
   @Override
   public void setPrice(double price) {
       //give 10% discount for science book
       this.price=price-price*0.10;      
   }

   @Override
   public String getGenre() {
       return "Science Book";
   }
   public double getPrice()
   {
       return this.price;
   }

}
*****************************************

ChildrenBook.java :

//Java class with name ChildrenBook that extends Book class
public class ChildrenBook extends Book {
   private double price;
   @Override
   public void setPrice(double price) {
       this.price=price;
      
   }

   @Override
   public String getGenre() {
       return "Children Book";
   }
   public double getPrice()
   {
       return this.price;
   }

}
*******************************************

BookDriver.java :

//import package
import javax.swing.*;

//Java class
public class BookDriver {
   // main() method
   public static void main(String[] args) {
       // Object of ScienceBook class
       ScienceBook sb = new ScienceBook();
       // asking user book title and set book title
       sb.setTitle(JOptionPane.showInputDialog(null, "Enter Book title : "));
       // asking user book ISBN and set book ISBN
       sb.setISBN(JOptionPane.showInputDialog(null, "Enter Book ISBN : "));
       // asking user book publisher and set book publisher
       sb.setPublisher(JOptionPane.showInputDialog(null, "Enter Book publisher : "));
       // asking user book year and set book year
       sb.setYear(Integer.parseInt(JOptionPane.showInputDialog(null, "Enter Book year : ")));
       // asking user book price and set book price
       sb.setPrice(Double.parseDouble(JOptionPane.showInputDialog(null, "Enter Book Price : ")));
       // print ScienceBook details
       JOptionPane.showMessageDialog(null, sb.toString() + "\nType : " + sb.getGenre() + "\n Price : " + sb.getPrice(),
               "Book Details", JOptionPane.INFORMATION_MESSAGE);
       // Object of ChildrenBook class
       ChildrenBook cb = new ChildrenBook();
       // asking user book title and set book title
       cb.setTitle(JOptionPane.showInputDialog(null, "Enter Book title : "));
       // asking user book ISBN and set book ISBN
       cb.setISBN(JOptionPane.showInputDialog(null, "Enter Book ISBN : "));
       // asking user book publisher and set book publisher
       cb.setPublisher(JOptionPane.showInputDialog(null, "Enter Book publisher : "));
       // asking user book year and set book year
       cb.setYear(Integer.parseInt(JOptionPane.showInputDialog(null, "Enter Book year : ")));
       // asking user book price and set book price
       cb.setPrice(Double.parseDouble(JOptionPane.showInputDialog(null, "Enter Book Price : ")));
       // print ScienceBook details
       JOptionPane.showMessageDialog(null, sb.toString() + "\nType : " + sb.getGenre() + "\n Price : " + sb.getPrice(),
               "Book Details", JOptionPane.INFORMATION_MESSAGE);
   }

}
===============================================

Screen asking book title :

Screen showing book details :