Question

Add locking to the Hotel class. Since it is going to be accessed by multiple threads, possibly simultaneously,

locking is required to ensure the data remains valid. Just lock all of the reservation information when necessary. This is a simple case, so you can either use a Lock object, or the synchronized keyword.

There is no need to use a condition, wait, await, signalAll, or notifyAll.

public enum RoomStatus {

EMPTY

NOT_EMPTY;

}

public enum PaymentStatus {

PAID,

UNPAID;

}

public enum Facility {

LIFT;

POWER_BACKUP;

HOT_WATERR;

BREAKFAST_FREE;

SWIMMING_POOL;

}

class User {

int userId;

String name;

Date dateOfBirth;

String mobNo;

String emailId;

String sex;

}

// For the room in hotel

class Hotel {

int hotelId;

String hotelName;

Information information;

// hotel contains the list of rooms

List<Room> rooms;

float rating;

Facilities facilities;

}

// a new booking is created for each booking

// done by any user

class Reservation {

int ReservationId;

int userId;

int hotelId;

// We are assuming that in a single

// booking we can book only the rooms

// of a single hotel

List<Rooms> bookedRooms;

int amount;

PaymentStatus status_of_payment;

Date bookingTime;

Duration duration;

}

class Information {

String city;

String pinCode;

String state;

String streetNo;

String landmark;

}

class Duration {

Date from;

Date to;

}

class Facilities {

List<Facility> facilitiesList;

}

In Java

Answer 1

public enum RoomStatus {

   EMPTY,

   NOT_EMPTY;

}

enum PaymentStatus {

   PAID,

   UNPAID;

}

enum Facility {

   LIFT,

   POWER_BACKUP,

   HOT_WATERR,

   BREAKFAST_FREE,

   SWIMMING_POOL;

}

class User {

   int userId;

   String name;

   Date dateOfBirth;

   String mobNo;

   String emailId;

   String sex;

}

// For the room in hotel

class Hotel implements Runnable{

   int hotelId;

   String hotelName;

   Information information;

// hotel contains the list of rooms

   List<Room> rooms;

   float rating;

   Facilities facilities;

   @Override
   public void run() {
       // TODO Auto-generated method stub
       Lock();
   }

   public void Lock()
{
System.out.println(Thread.currentThread().getName());
synchronized(Hotel.class)
{
System.out.println("Hotel class is locked down using Sychronized Keword.");
}
}
      
      
  
}

// a new booking is created for each booking

// done by any user

class Reservation {

   int ReservationId;

   int userId;

   int hotelId;

// We are assuming that in a single

// booking we can book only the rooms

// of a single hotel

   List<Room> bookedRooms;

   int amount;

   PaymentStatus status_of_payment;

   Date bookingTime;

   Duration duration;

}

class Information {

   String city;

   String pinCode;

   String state;

   String streetNo;

   String landmark;

}

class Duration {

   Date from;

   Date to;

}

class Facilities {

   List<Facility> facilitiesList;

}

Here Hotel class is locked using runnable interface, run() method and synchronised keyword.