Problem:
Reservation
|
+
reserveSeat(seatNumber : int) : void
+
reserveSeats(seatN umbers : int[]) : void
+
cancelReservation(seatNumber : int) : void
+
cancelReservations(seatNumbers : int[]) : void
|
MovieReservation
|
-
seats : int[]
|
+
MovieReservation(seats : int[])
+
reserveSeat(seatNumber : int) : void
+
reserveSeats(seatN umbers : int[]) : void
+ cancelReservation(seatNumber : int) : void
+
cancelReservations(seatNumbers : int[]) : void
+ toString() : String
|
TravelTicketReservation
|
-
seats : int[]
|
+
TravelTicketReservation(seats : int[])
+
reserveSeat(seatN umber : int) : void
+
reserveSeats(seatN umbers : int[]) : void
+
cancelReservation(seatNumber : int) : void
+
cancelReservations(seatNumbers : int[]) : void
+ toString() : String
|
SeatException
|
+
SeatException(message : String)
|
In
this lab, you will be creating a Movie Reservation System and a Travel Ticket
Reservation that will implement an interface, and a SeatException class.
The
Reservation interface has five methods that need to be implemented which are
reserveSeat, reserveSeats, cancelReservation, and cancelReservations.
The
SeatException class will extend the Java Exception class. Its constructor will
take a string as a parameter and call the superclass' constructor passing the
string to it as a parameter.
The
MovieReservation class and the TravelTicketReservation class will implement the
interface's methods. They also have a private variable which is an array of
integers representing the seats. The constructor should initialize this
variable.
The
reserveSeat method will take an integer named seatNumber as a parameter and
sets seats[seatNumber] to one indicating that the seat is reserved. If the seat
is already reserved, a SeatException should be thrown.
The
reserveSeats method will take an integer array named seatNumbers as a parameter
and sets all the seat numbers in the array to one indicating that the seat is
reserved. If the seat is already reserved, a SeatException should be thrown.
The
cancelReservation method will take an integer named seatNumber as a parameter
and sets seat[seatNumber] to zero indicating that the seat is empty. If the
seat is already empty, a SeatException should be thrown.
The
cancelReservations method will take an integer array named seatNumbers as a
parameter and sets all the seat numbers in the array to zero indicating that
the seat is empty. If the seat is already empty, a SeatException should be
thrown.
You
should write a tester class that will have an instance of MovieReservation and
TravelTicketReservation and then call the previous methods. You should use try
and catch blocks to handle the exceptions that might be thrown in these
methods.
For
each instance, the tester class should read input from the user by using a
scanner. For simplicity, make the number of seats ten. First, the user must
enter ten numbers which are either zero or one, so use a for loop to read ten
numbers and set the value of seats[i] to the read value.
Then,
read an int value from the user and call reserveSeat passing the value as a
parameter. Then, read four int values from the user and call reserveSeats
passing the values as a parameter. Then do the same thing for cancelReservation
and cancelReservations.
There
are three types of exceptions that can happen when calling these functions. The
first one is a SeatException as discussed earlier. The second one is an
IndexOutOfBoundsException which will occur if the user enters a number that is
less than zero or greater that seats.length. The third one is an
InputMismatchException if the user enters a value which is not an integer.
After
each call to the functions, you should print the seats array, or print
"Seat number does not exist" if an IndexOutOfBoundsException occurs,
or "Seat already reserved or empty" if a SeatException occurs, or
"Input should be an Integer" if an InputMismatchException occurs.
Solution:
/**------------------Reservation.java--------------*/
public interface Reservation {
public void reserveSeat(int seatNumber) throws SeatException;
public void reserveSeats(int seatNumbers[]) throws SeatException;
public void cancelReservation(int seatNumber) throws SeatException;
public void cancelReservations(int seatNumbers[]) throws SeatException;
}
/**------------------MovieReservation.java---------*/
public class MovieReservation implements Reservation {
private int seats[];
public MovieReservation(int seats[]) {
this.seats = seats;
}
@Override
public void reserveSeat(int seatNumber) throws SeatException {
if (seats[seatNumber] == 1)
throw new SeatException("Seat already reserved");
else
seats[seatNumber] = 1;
}
@Override
public void reserveSeats(int[] seatNumbers) throws SeatException {
for (int i = 0; i < seatNumbers.length; i++) {
if (seats[seatNumbers[i]] == 1)
throw new SeatException("Seat already reserved");
else
seats[seatNumbers[i]] = 1;
}
}
@Override
public void cancelReservation(int seatNumber) throws SeatException {
if (seats[seatNumber] == 0)
throw new SeatException("Seat already empty");
else
seats[seatNumber] = 0;
}
@Override
public void cancelReservations(int[] seatNumbers) throws SeatException {
for (int i = 0; i < seatNumbers.length; i++) {
if (seats[seatNumbers[i]] == 0)
throw new SeatException("Seat already empty");
else
seats[seatNumbers[i]] = 0;
}
}
public String toString() {
return "";
}
}
/**-------------TravelTicketReservation.java-------*/
public class TravelTicketReservation implements Reservation {
private int seats[];
public TravelTicketReservation(int seats[]) {
this.seats = seats;
}
@Override
public void reserveSeat(int seatNumber) throws SeatException {
if (seats[seatNumber] == 1)
throw new SeatException("Seat already reserved");
else
seats[seatNumber] = 1;
}
@Override
public void reserveSeats(int[] seatNumbers) throws SeatException {
for (int i = 0; i < seatNumbers.length; i++) {
if (seats[seatNumbers[i]] == 1)
throw new SeatException("Seat already reserved");
else
seats[seatNumbers[i]] = 1;
}
}
@Override
public void cancelReservation(int seatNumber) throws SeatException {
if (seats[seatNumber] == 0)
throw new SeatException("Seat already empty");
else
seats[seatNumber] = 0;
}
@Override
public void cancelReservations(int[] seatNumbers) throws SeatException {
for (int i = 0; i < seatNumbers.length; i++) {
if (seats[seatNumbers[i]] == 0)
throw new SeatException("Seat already empty");
else
seats[seatNumbers[i]] = 0;
}
}
public String toString() {
return "";
}
}
/**------------------SeatException.java------------*/
public class SeatException extends Exception {
//simple
public SeatException(String message) {
super(message);
}
}
/**------------------Tester.java-------------------*/
import java.util.InputMismatchException;
import java.util.Scanner;
public class Tester {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
int seats[] = new int[10];
System.out.print("Please initialize seats: ");
for (int i = 0; i < seats.length; i++)
seats[i] = scan.nextInt();
MovieReservation movieReservation = new MovieReservation(seats);
try {
System.out.print("Enter a seat number to reserve: ");
int seatNumber = scan.nextInt();
movieReservation.reserveSeat(seatNumber);
System.out.println("Seat reserved successfully");
/**-------------------------------------------*/
System.out.println("Enter four seats to reserve: ");
int seatNumbers[] = new int[4];
for (int i = 0; i < seatNumbers.length; i++)
seatNumbers[i] = scan.nextInt();
movieReservation.reserveSeats(seatNumbers);
System.out.println("Seats reserved successfully");
/**-------------------------------------------*/
System.out.print("Enter a seat number to cancel: ");
seatNumber = scan.nextInt();
movieReservation.cancelReservation(seatNumber);
System.out.println("Seat cancelled successfully");
/**-------------------------------------------*/
System.out.println("Enter four seats to cancel: ");
seatNumbers = new int[4];
for (int i = 0; i < seatNumbers.length; i++)
seatNumbers[i] = scan.nextInt();
movieReservation.cancelReservations(seatNumbers);
System.out.println("Seats cancelled successfully");
} catch (SeatException e) {
System.out.println("Error: could not reserve or cancel seat");
} catch (ArrayIndexOutOfBoundsException e) {
System.out.println("Error: entered number must be greater than -1 and less than 10");
} catch (InputMismatchException e) {
System.out.println("Error: entered value must be a number");
}
scan.close();
}
}
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