Assignment 1
COMP 250 Winter 2020
posted: Friday, Jan. 24, 2020
due: Sunday, Feb. 9, 2020 at 23:59
Learning Objectives
This assignment is meant for you to practice what we have learned in class in the first 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 influenced 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 efficiency for the first assignments, but your implementation decisions
can affect how efficient the code for this assignment is. Try to keep this in mind while coding.
Make sure to ask yourselves why certain modifiers (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 file submitted, wrong file 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 first version a few days before the deadline (computer crashes do happen
and myCourses may be overloaded during rush hours).
– Please store all your files in a folder called “Assignment1”, zip the folder and submit it
to myCourses. Inside your zipped folder, there must be the following files.
∗ Airport.java
∗ Room.java
∗ Hotel.java
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∗ Reservation.java
∗ FlightReservation.java
∗ HotelReservation.java
∗ BnBReservation.java
∗ Basket.java
∗ Customer.java
Do not submit any other files, especially .class files. 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
figure 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 final 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 office hours, or on the discussion board
on Piazza.
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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 simplifications 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 fields (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 fields:
• 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 fields.
• 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:
distance =
√
(x1 − x2)2 + (y1 − y2)2
[12 points] Write a class Room. An room has the following private fields:
• 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 fields.
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.
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• A constructor that takes a Room as input and creates a copy of the input room (i.e. it
initialize the fields using the values from the corresponding fields 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 field 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 first 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 first 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 fields:
• 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 fields. Note that the array used to initialize
the field 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 first available room of the specified
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 field:
• 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 field.
• A final reservationName method to retrieve the name on this reservation.
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• 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
different 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 fields:
– 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 fields.
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
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∗ Planes pay $1.24 per gallon of fuel.
∗ Planes can fly 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 flight cost of 103568.21187 cents, the method should
return 103569 cents instead. You may assume that the cost of all reservations fits
within an int and therefore doesn’t cause overflow.
– 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 fields:
– 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.
1See: https://youtu.be/6Oe8T3AvydU
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– An int indicating the price (in cents) for one night in a room of the specified type
in the specified 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 fields. The constructor should also make sure to reserve a room of the
correct type in the specified 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 specified 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 fields, 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 specific. 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 difference in terms of how efficient your code will be. We will not
be deducting point for inefficient 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 field:
• An array of Reservations.
The class must also have the following public methods:
• A constructor that takes no inputs and initialize the field 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
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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 first occurrence of the specified 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 flight reservations from Montreal to Vancouver are not
considered equal if they were created under two different 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 fields:
– 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 fields.
– 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.
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– 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 flight 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.
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