Assignment 1 Solution

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Description

Market Place

For this assignment you will write several classes to simulate an online Market place. Make sure to follow the instructions below very closely. Note that in addition to the required methods, you are free to add as many other private methods as you want (no other additional method is allowed).

[10 points] Write an abstract class MarketProduct which has the following private eld:

A String name

The class must also have the following public methods:

A constructor that takes a String as input indicating the name of product and uses it to initialize the corresponding attribute.

A final getName() method to retrieve the name of this MarketProduct.

An abstract method getCost() which takes no input and returns an int. This method should be abstract (thus, not implemented) because how to determine the cost depends on the type of product.

An abstract method equals() which takes an Object as an input and returns a boolean. This method should be abstract as well, since depending on the type of product di erent conditions should be met in order for two products to be considered equal.

[25 points] All of the followings must be subclasses of the MarketProduct:

Write a class Egg derived from the MarketProduct class. The Egg class has the following private elds:

{ An int indicating the number of eggs.

{ An int indicating the price per dozen of these eggs. Note that the all the prices (throughout the assignment) are indicated in cents. For instance, 450 represents the amount $4.50.

The Egg class has also the following public methods:

{ A constructor that takes as input a String with the name of the product, an int indicating the number required, and an int indicating the price of such product by the dozen. The constructor uses the inputs to create a MarketProduct and initialize the corresponding elds.

{ A getCost() method that takes no input and returns the cost of the product in cents. The cost is computed base on the number required and the cost per dozen. For instance, 4 large brown eggs at 380 cents/dozen cost 126 cents (the cost should be rounded down to the nearest cent). You may assume that cost of all MarketProducts ts within an int and therefore doesn’t cause over ow.

{ An equals() method which takes as input an Object and return true if input matches this in type, name, cost and number of eggs. Otherwise the method returns false.

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Write a class Fruit derived from the MarketProduct class. The Fruit class has the following private elds:

{ A double indicating the weight in kg.

{ An int indicating the price per kg in cents.

The Fruit class has also the following public methods:

{ A constructor that takes as input a String with the name of the product, a double indicating the weight in kg, and an int indicating the price per kg of such prod-uct. The constructor uses the inputs to create a MarketProduct and initialize the corresponding elds.

{ A getCost() method that takes no input and returns the cost of the product in cents. The cost is computed based on the weight and the price per kilogram. For instance, 1.25 kgs of asian pears at 530 cents per kg cost 662 cents.

{ An equals() method just like the Egg class, which matches type, name, weight and cost.

Write a class Jam derived from the MarketProduct class. The Jam class has the following private elds:

{ An int indicating the number of jars.

{ An int indicating the price per jar in cents.

The Jam class has also the following public methods:

{ A constructor that takes as input a String with the name of the product, an int indicating the number of jars, and an int indicating the price per jar of such prod-uct. The constructor uses the inputs to create a MarketProduct and initialize the corresponding elds.

{ A getCost() method that takes no input and returns the cost of the product in cents. The cost is computed based on the number of jars and their price. For instance, 2 jars of Strawberry jam at 475 cents per jar cost 950 cents.

{ An equals() method like in the previous classes.

Write a class SeasonalFruit derived from the Fruit class. The SeasonalFruit class has no elds, but it has the following public methods:

{ A constructor that takes as input a String with the name of the product, a double indicating the weight in kg, and an int indicating the price per kg of such product. The constructor uses the inputs to create a Fruit.

{ A getCost() method that takes no input and returns the cost of the product in cents. Since this type of Fruit is in season, its original cost should receive a 15% discount. For instance, 0.5 kgs of McIntosh apples at 480 cents per kg cost 204 cents.

[40 points] Write a class Basket which has the following private eld:

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An array of MarketProducts.

The class must also have the following public methods:

A constructor that takes no inputs and initialize the eld with an empty array.

A getProducts() method which takes no inputs and returns a shallow copy of the array (NOT a copy of the reference!) of MarketProducts of this Basket (with the elements in the same order).

An add() method which takes as input a MarketProduct and does not return any value. The method adds the MarketProduct at the end of the array of products of this Basket.

A remove() method which takes as input a MarketProduct and returns a boolean. The method removes the rst occurrence of the speci ed element from the array of products of this Basket. If no such product exists, then the method returns false, otherwise, after removing it, the method returns true. Note that this method removes the the whole product. For example, it is not possible to remove 0.25 Kg of McIntosh apples for a 0.5 Kg McIntosh apples MarketProduct. After the product has been remove from the array, the subsequent elements should be shifted down by one position, leaving no empty slot in the array.

A clear() method which takes no inputs, returns no values, and empties the array of products of this Basket.

A getNumOfProducts() method that takes no inputs and returns the number of products present in this Basket.

A getSubTotal() method that takes no inputs and returns the cost (in cents) of all the products in this Basket.

A getTotalTax() method that takes no inputs and returns the tax amount (in cents) to be paid based on the product in this Basket. Since we are in Quebec, you can use a tax rate of 15%. The tax amount should be rounded down to the nearest cent. Note that Egg and Fruit are tax free, so taxes should be paid only for Jam.

A getTotalCost() method that takes no inputs and returns the total cost (in cents and after tax) of the products in this Basket.

A toString() method that returns a String representing a receipt for this Basket. The receipt should contain a product per line. On each line the name of the product should appear, followed by its price separated by a tab character. After all the products have been listed, the following information should appear on each line:

{ An empty line

{ The subtotal cost { The total tax

{ An empty line { The total cost

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Note that all the integer number of cents should be transformed into a String formatted in dollars and cents (you can write a helper method to do so if you’d like). If the number of cents is represented by an int that is less than or equal to 0, then it should be transformed into a String containing only the hyphen character (“-“). An example of a receipt is as follows:

Quail eggs 4.00

McIntosh apples 6.12

Asian Pears 4.24

Blueberry Jam 4.75

Subtotal 23.86

Total Tax 0.71

Total Cost 24.57

[25 points] Write a class Customer which has the following private elds:

A String name

An int representing the balance (in cents) of the customer

A Basket containing the products the customer would like to buy. The class must also have the following public methods:

A constructor that takes as input a String indicating the name of the customer, and an int representing their initial balance. The constructor uses its inputs and creates an empty Basket to initialize the corresponding elds.

A getName() and a getBalance() method which return the name and balance (in cents) of the customer respectively.

A getBasket() method which returns the reference to the Basket of this Customer (no copy of the Basket is needed).

An addFunds() method which takes an int as input representing the amount of cents to be added to the balance of this Customer. If the input received is negative, the method should throw an IllegalArgumentException with an appropriate message. Otherwise, the method will simply update the balance and return the new balance in cents.

An addToBasket() method which takes a MarketProduct as input and adds it to the basket of this Customer. This method should not return anything.

A removeFromBasket() method which takes a MarketProduct as input and removes it from the basket of this Customer. The method returns a boolean indicating whether of not the operation was successful.

A checkOut() method which takes no input and returns the receipt for the customer as a String. If this Customer’s balance is not enough to cover the total cost of their

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basket, then the method throws an IllegalStateException. Otherwise, this Customer is charged the total cost of the basket and a receipt is returned.

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