Question

For this question,  we want to implement the basic java classes to support the concept of an Online Store and a shopping cart.
Consider an e-store with various types of items: books, flowers, gift cards, etc... and we like to be able to support the ability to handle a shopping cart that can contain various types of items.

For this question you are asked to create the following classes:

abstract class: “Item”
every item has a unique item_id (a positive integer, auto-incremented for each new item), a price (double, 0 or positive), and quantity (integer, 0 or positive), Title (String, cannot be empty).Every item can be “Display()”, an abstract method, and “Purchase()” (that is removed from the inventory).

concrete class: “Book”
a Book is-an item. It adds the attributes “author”, “title” and “year”.

concrete class: “GiftCard”
a GiftCard is-an item. It adds the attributes “label”, and “manufacturer”.

concrete class: “Shoe”
a Shoe is-an item. It adds the attributes “colour” (a String one of these colours: white, silver, red, beige, brown, blue, black, pink), and “size” (double).

Write an application that maintains a list of items entered from the user by means of an interactive menu.

The user can:

Add item to the inventory, entering its type (book or gift card, etc), and necessary attributes along with quantity.

Display all items.

Display only books sorted by author name.

Display only gifts sorted by label.

Display only shoes sorted by sizeDelete an item by item_id

Purchase an item by removing the purchased quantity from the inventory

You should:  Save items to a file, and loading them back, using object serialization.

You should: use a linked list to enable dynamic size for the e-store,  instead of array object .


Write all necessary classes and methods to ensure the responsibility driven assignment of classes in a pure object-oriented approach enforcing all business rules. Document all the rules and classes using Javadoc compatible documentation.

Answer 1

Answer: I have written an abstract class Item along with concrete classes Book, GiftCard, Shoe as demanded in the question using object orientated techniques.

Note: You may refer to screenshots below to have better understanding of the indentation.

Code:

import java.util.LinkedList;

abstract class Item{
   private static int count = 0;
   protected int itemID;
   protected double price;
   protected int quantity;
   protected String title;
  
   public abstract void display();
   public abstract void purchase();
  
   public Item()
   {
       itemID = ++count;
   }
}

class Book extends Item{
  
   private String author;
   private int year;
   private String bookTitle;

   public Book(String title, double price, int quantity, String author,String bookTitle, int year)
   {
       this.price = price;
       this.quantity = quantity;
       this.title = title;
       this.author = author;
       this.bookTitle = bookTitle;
       this.year = year;
   }
  
   @Override
   public void display() {
       System.out.println("Book id: " + itemID + ", Price: " + price + ", Quantity: " + quantity + ", Author: " + author + ", year: " + year);
   }

   @Override
   public void purchase() {
       quantity = quantity - 1;
   }
  
}

class GiftCard extends Item{

   private String label;
   private String manufacturer;
  
   public GiftCard(String title, double price, int quantity, String label, String manufacturer)
   {
       this.price = price;
       this.quantity = quantity;
       this.title = title;
       this.label = label;
       this.manufacturer = manufacturer;
   }
  
   @Override
   public void display() {
       System.out.println("GiftCard id: " + itemID + ", Price: " + price + ", Quantity: " + quantity + ", Label: " + label + ", Manufacturer: " + manufacturer);
   }

   @Override
   public void purchase() {
       quantity = quantity - 1;
   }
  
}

class Shoe extends Item{

   private String color;
   private double size;
  
   public Shoe(String title, double price, int quantity, String color, double size)
   {
       this.price = price;
       this.quantity = quantity;
       this.title = title;
       this.color = color;
       this.size = size;
   }
  
   @Override
   public void display() {
       System.out.println("Shoe id: " + itemID + ", Price: " + price + ", Quantity: " + quantity + ", Color: " + color + ", Size: " + size);
      
   }

   @Override
   public void purchase() {
       quantity = quantity - 1;
   }
  
}

public class ShoppingCart2 {

   // create a list object to store the items
   static LinkedList<Item> items = new LinkedList<Item>();
  
   public static void main(String[] args) {
      
       Item i1 = new Shoe("Shoe",50,10,"black",6);
       Item i2 = new Book("Book",10.0,20,"Dan Brown","Deception Point", 2001);
       Item i3 = new Shoe("Shoe",100,5,"pink",8);
       Item i4 = new GiftCard("GiftCard",2,50,"Friends","abc");
       Item i5 = new Book("Book",6.0,15,"Famous", "fRIENDS",1990);
      
       //add items in the list
       items.add(i1);
       items.add(i2);
       items.add(i3);
       items.add(i4);
       items.add(i5);
      
       //display all items
       System.out.println("All items in the store: ");
       for (Item item : items) {
       item.display();
       }
      
       //display books
       System.out.println("\nBooks in the store: ");
       for(Item item : items) {
           if(item.title == "Book") {
               item.display();
           }
       }
      
       //display gifts
       System.out.println("\nGifts in the store: ");
       for(Item item : items) {
           if(item.title == "GiftCard") {
               item.display();
           }
       }
      
       //display shoes
       System.out.println("\nShoes in the store: ");
       for(Item item : items) {
           if(item.title == "Shoe") {
               item.display();
           }
       }

   }

}

Output:

Screenshots of the code: