COMP 250 Assignment 1 Solved

Learning Objectives

This assignment is meant for you to practice what we have learned in class in the rst four weeks of the semester. A lot of the design decision have been taken for you, but it is important for you to ask yourself why each choice has been made and whether there could be a better way of doing it. Some of our choices were in uenced by the intention of having you practice most of what you have learned in class. Others, were dictated by our need to be able to fully test your assignments. Finally, we will not be grading your work on e ciency for the rst assignments, but your implementation decisions can a ect how e cient the code for this assignment is. Try to keep this in mind while coding. Make sure to ask yourselves why certain modi ers (private, public, static,...) were used and if you would have made the same decisions. We hope that the assignment will help you appreciate the importance of class design. This is of course just a taste, you will learn much more about it in COMP 303. As mentioned in class, we suggest you take the time to draw out a class diagram. This should help you develop a clear picture of the relationship between all these classes.


General Instructions

Submission instructions

{ Late assignments will be accepted up to 2 days late and will be penalized by 10 points per day. Note that submitting one minute late is the same as submitting 23 hours late. We will deduct 10 points for any student who has to resubmit after the due date (i.e. late) irrespective of the reason, be it wrong le submitted, wrong le format was submitted or any other reason. This policy will hold regardless of whether or not the student can provide proof that the assignment was indeed \done" on time.

{ Don’t worry if you realize that you made a mistake after you submitted: you can submit multiple times but only the latest submission will be evaluated. We encourage you to submit a rst version a few days before the deadline (computer crashes do happen and myCourses may be overloaded during rush hours).

{ Please store all your les in a folder called \Assignment1", zip the folder and submit it to myCourses. Inside your zipped folder, there must be the following les.

Airport.java Room.java

Hotel.java

1

Reservation.java

FlightReservation.java HotelReservation.java BnBReservation.java

Basket.java Customer.java

Do not submit any other les, especially .class les. Any deviation from these requirements may lead to lost marks

It does not matter whether or not you create a package to store all these classes. It is up to you to decide whether you’d like to have a package or not.

You will have to create all the above classes from scratch. The assignment shall be graded automatically. Requests to evaluate the assignment manually shall not be entertained, so please make sure that you follow the instruction closely or your code may fail to pass the automatic tests. Note that for this assignment, you are NOT allowed to import any other class (including for example ArrayList or LinkedList). Any failure to comply with these rules will give you an automatic 0.

We have included with these instructions a SyntaxTester class, which is meant to help you gure out whether you have correctly followed the instructions in terms of class names and methods’ headers. Note that, if the SyntaxTester raises an error this means that we will not be able to test your assignment and it will result in an automatic 0.

Early next week we will release a mini tester which is a mini version of the nal tester used to evaluate your assignment. If your code fails those tests, it means that there is a mistake somewhere. Even if your code passes those tests, it may still contain some errors. We will test your code on a much more challenging set of examples. We therefore highly encourage you to modify the tester class and expand it.

You will automatically get 0 if your code does not compile.

Failure to comply with any of these rules will be penalized. If anything is unclear, it is up to you to clarify it by asking either directly a TA during o ce hours, or on the discussion board on Piazza.
















2

Travel Agency

For this assignment you will write several classes to simulate an online travel agency. Note that for this assignment to be feasible in two weeks, a lot of simpli cations have been made. For instance, we are completely ignoring time throughout the assignment. 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). You are not allowed to add any additional elds (whether they would be private or public) unless it is stated otherwise. Finally, whenever you are required to compare two strings you can ignore case of the characters.

[12 points] Write a class Airport. An airport has the following private  elds:

An int indicating the x-coordinate of the airport on a world map with a scale to 1 km. An int indicating the y-coordinate of the airport on a world map with a scale to 1 km. An int indicating the airport fees (in cents) associated to this airport.

The class must also have the following public methods:

A constructor that takes three int as input indicating the position of the airport on a map (x and y coordinate) and the fees of the airport (in cents) respectively. The constructor uses the inputs to initialize the corresponding elds.

A getFees method to retrieve the fees of the airport.

A static method getDistance which takes as input two airport and returns a integer indicating the distance in kilometer between the two airports.  Note that the method should round the distance up (e.g. both 5:9 and 5:2 should become 6). More over, remember that given two points (x1; y1) and (x2; y2), the distance can be computed with

the following formula:
p

distance =    (x1    x2)2 + (y1    y2)2

[12 points] Write a class Room. An room has the following private  elds:

A String indicating the type of the room.

An int indicating the price (in cents) of the room.

A boolean indicating whether or not the room is available. The class must also have the following public methods:

A constructor that takes as input the type of the room and uses it to initialize the elds. Note that there are only 3 type of rooms supported by the program: double, queen, and king. If the input does not match one of these room type, then the constructor should throw an IllegalArgumentException explaining that no room of such type can be created. The price of the room is based on its type as follows: $90 for a double, $110 for a queen, $150 for a king. Remember that the price should be stored in cents. The constructor should set the availability for a new room to be true.

3

A constructor that takes a Room as input and creates a copy of the input room (i.e. it initialize the elds using the values from the corresponding elds of the input room).

A getType and a getPrice method which return the type and the price of the room respectively.

A changeAvailability method which takes no input and sets the value stored in the availability eld to be the opposite of the one currently there.

A static method findAvailableRoom which takes as input an array of Rooms as well as a String indicating a room type. The method should return the rst available room in the array of the indicated type. If no such room exists (either because all rooms of said type are occupied, or because no room of such type is in the array), the method returns null. Note that, no changes to any of the rooms in the input array should be made by this method!

A static method makeRoomAvailable which takes as input an array of Rooms as well as a String indicating a room type. The method should make the rst unavailable room in the array of the indicated type available again. If successful, the method should return true, otherwise the method should return false.

[12 points] Write a class Hotel. An hotel has the following private  elds:

An String indicating the name of the hotel.

An array of Rooms indicating the rooms in the hotel. The class must also have the following public methods:

A constructor that takes a String and an array of Rooms respectively. The constructor uses the inputs to initialize the corresponding elds. Note that the array used to initialize the eld representing the rooms should be a deep copy of the input array.

A reserveRoom method which takes as input a String indicating the type of room to reserve. The method changes the availability of the rst available room of the speci ed type in the hotel. If successful, the method returns the price of the room. Otherwise, an IllegalArgumentException should be thrown.

A method cancelRoom which takes as input a String indicating the type of room to cancel. The method makes a room of that type available again. It returns true if it operation was possible, false otherwise.

[5 points] Write an abstract class Reservation 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 the client on the reservation and uses it to initialize the corresponding eld.

A final reservationName method to retrieve the name on this reservation.



4

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 reservation.

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 reservation di erent conditions should be met in order for two reservations to be considered equal.

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

Write a class FlightReservation derived from the Reservation class. This class has the following private elds:

{ An Airport indicating the place of departure. { An Airport indicating the place of arrival.

The class has also the following public methods:

{ A constructor that takes as input a String with the name on the reservation, and two Airports indicating the place of departure and arrival respectively. The constructor uses the inputs to create a Reservation and initialize the corresponding elds. Throw an IllegalArgumentException if the two input airports are the same. Ignore the fact that you did not overrode the equals method in the Airport class.

{ A getCost method that takes no input and returns the cost of the reservation (an int) in cents. The cost is computed adding together the fuels cost, the aiports fees, and $53.75 (which include costs related to the plane plus taxes). You can assume that 1:

Planes pay $1.24 per gallon of fuel.

Planes can  y 167.52 kilometer per gallon of fuel.

The cost should be rounded up to the nearest cent. For example, if after the computation above you obtain a ight cost of 103568:21187 cents, the method should return 103569 cents instead. You may assume that the cost of all reservations 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, and airports. Otherwise the method returns false. You can ignore the fact that you did not overrode the equals method in the Airport class.

Write a class HotelReservation derived from the Reservation class. This class has the following private elds:

{ An Hotel indicating where to make the reservation. { A String indicating the type of room to reserve.

{ An int indicating the number of nights to be spent in the hotel.


    • See: https://youtu.be/6Oe8T3AvydU


5

{ An int indicating the price (in cents) for one night in a room of the speci ed type in the speci ed hotel.

The class has also the following public methods:

{ A constructor that takes as input a String with the name on the reservation, a Hotel, a String with the room type, and an int indicating the number of nights. The constructor uses the inputs to create a Reservation and initialize the corre-sponding elds. The constructor should also make sure to reserve a room of the correct type in the speci ed hotel. If such reservation is not possible, then an IllegalArgumentException should be raised.

{ A getNumOfNights method to retrieve the number of night on the reservation.

{ A getCost method that takes no input and returns the cost of the reservation (an int) in cents. The cost represents the price to pay for the speci ed type of room given the number of nights indicated in the reservation.

{ An equals method which takes as input an Object and return true if input matches this in type, name, hotel, room type, number of nights, and total cost. Otherwise the method returns false. Once again, you can ignore the fact that you did not overrode the equals method in the Hotel class.

Write a class BnBReservation derived from the HotelReservation class. This class has no elds, but it has the following public methods:

{ A constructor that takes as input a String with the name on the reservation, a Hotel, a String with the room type, and an int indicating the number of nights. The constructor uses the inputs to create an HotelReservation.

{ A getCost method that takes no input and returns the cost of the reservation (an int) in cents. Since this reservation includes breakfast, to the cost of reserving the room in the hotel you should add $10 per night.

[18 points] Write a class Basket representing a list of reservations. Note that the instructions on how to implement this class are not always very speci c. This is intentional, since your assignment will not be tested on the missing details of the implementation. Note though, that your choices will make a di erence in terms of how e cient your code will be. We will not be deducting point for ine cient code in Assignment 1. Note once again that, you are NOT allowed to import any other class (including ArrayList or LinkedList). The class has (at least) the following private eld:

An array of Reservations.

The class must also have the following public methods:

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

A getProducts method which takes no inputs and returns a shallow copy of the array of Reservations of the basket. This array should contain all the reservations in


6

the basket in the same order in which they were added.

An add method which takes as input a Reservation. The method adds the reservation at the end of the list of reservation of the basket and returns how many reservations are now there.

A remove method which takes as input a Reservation and returns a boolean. The method removes the rst occurrence of the speci ed element from the array of reser-vation of the basket. If no such reservation exists, then the method returns false, otherwise, after removing it, the method returns true. Note that this method removes a reservation from the list if and only if such reservation is equal to the in-put received. For example, two ight reservations from Montreal to Vancouver are not considered equal if they were created under two di erent names. After the reservation has been removed from the array, the subsequent elements should be shifted down by one position, leaving no unutilized slots in the middle array.

A clear method which takes no inputs, returns no values, and empties the array of reservations of the basket.

A getNumOfReservations method that takes no inputs and returns the number of reser-vations in the basket.

A getTotalCost method that takes no inputs and returns the cost (in cents) of all the reservations in the basket.

[16 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 reservations the customer would like to make. 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 the 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 the 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.




7

{ An addToBasket method which takes a Reservation as input and adds it to the basket of the customer if the name on the reservation matches the name of the customer. If the method is successful it should return the number of reserva-tions in the basket of this customer. Otherwise, the method should throw an IllegalArgumentException.

{ An addToBasket method which takes a Hotel, a String representing a room type, an int representing the number of nights, and a boolean representing whether or not the customer wants breakfast to be included. The method adds the corresponding reservation to the basket of the customer and returns the number of reservations that are now in the basket of this customer.

{ An addToBasket method which takes two Airports as input. The method adds the corresponding reservation to the basket of the customer and returns the number of reservations that are now in their basket, whether or not the ight reservation was created successfully.

{ A removeFromBasket method which takes a Reservation as input and removes it from the basket of the customer. The method returns a boolean indicating whether of not the operation was successful.

{ A checkOut method which takes no input. If the customer’s balance is not enough to cover the total cost of their basket, then the method throws an IllegalStateException. Otherwise, the customer is charged the total cost of the basket, the basket is cleared, and balance left is returned.

































8