problemhardood

Object-Oriented Design for a Movie Ticket Booking System

Hard

Problem

Design an object-oriented system for an online movie ticket booking platform where users search movies by city, view theaters and showtimes, select seats, and complete payment while handling seat concurrency and status tracking.

Solution

1. Requirements Analysis

Functional Requirements:

  • Search movies playing in a specified city.
  • View theaters, showtimes, and movie details.
  • Select seats (normal/executive/premium/VIP) and initiate booking.
  • Prevent double-booking: seats must be locked during selection/payment.
  • Process payment and mark booking as paid/unpaid.
  • Track booking details (user, movie, show time, seats, amount, payment status, booking timestamp).
  • Maintain movie availability status (available / not available).
  • Rate theaters (stored rating attribute).

Non-Functional Requirements (minimal):

  • Concurrency control for seat selection (e.g., synchronized locking mechanism).
  • Reliability: seat state must accurately reflect availability.
  • Extensibility: easy addition of new seat types or payment statuses.

2. Use Case Diagram

Actors: User, System (for seat locking/payment processing).

Use Case Summary: A User first searches for movies playing in a chosen city. After selecting a movie, the User views theaters and showtimes, then enters interactive seat selection. The System helps by presenting current seat availability and temporarily locking chosen seats to prevent race conditions. Once seats are selected, the User confirms a booking and initiates payment. The System processes the transaction—on success it finalizes the booking and issues confirmation; on failure it releases seat locks. At any time the User can retrieve booking status (paid/unpaid and seat allocation).

Use Cases: Search Movie, View Theater Details, Select Seats, Book Tickets, Make Payment, View Booking Status.

graph TD
  subgraph BookingSystem
    UC_Search(Search Movie by City)
    UC_View(View Theater & Showtimes)
    UC_Select(Select Seats)
    UC_Book(Book Tickets)
    UC_Pay(Make Payment)
    UC_Status(View Booking Status)
  end
  User --> UC_Search
  User --> UC_View
  User --> UC_Select
  User --> UC_Book
  User --> UC_Pay
  User --> UC_Status
  System --> UC_Select
  System --> UC_Pay

Movie Booking System Reference

3. Class Diagram

Detailed Class Explanations:

  • User: Represents the customer performing searches and bookings. Stores personal profile data (name, contact info, birth date, gender) used for confirmations and potential age-based restrictions in future extensions.
  • Movie: Captures a film available for booking including a link to the theater where it is showing (simplified direct association), its language/type and current availability status. In a fuller design movies would map to multiple theaters via showtimes; here we retain provided single theaterId.
  • Theater: Aggregates movies currently running at a physical location. Holds identification, address, and a rating used for display ordering. The list of movies enables quick in-memory iteration for search results filtered by city.
  • Address: Value object bundling location attributes for a theater (city, state, pinCode, street, landmark) to avoid scattering raw strings.
  • Booking: Encapsulates a ticket purchase: references user and movie, the seats chosen (represented as a list placeholder—real design would use seat identifiers), monetary amount, payment status, booking timestamp and show timing. Transition of status_of_payment drives confirmation logic.
  • Facilities: Placeholder for extensible amenities (parking, food court, accessibility) that could influence theater filtering; retained without attributes per source.
  • Enumerations (SeatStatus, MovieStatus, MovieType, SeatType, PaymentStatus): Define constrained domains for various stateful or categorical fields ensuring validity (e.g., a seat can't be in an arbitrary string state).
  • SeatBook (Conceptual Seat Manager): Provides operations for checking availability, determining seat position, handling multi-seat selections, and committing final booking which triggers payment. Represents the concurrency boundary where locks would be applied.
  • Transaction: Abstracts payment processing; invoked by SeatBook during final booking to charge user and update booking state upon success or failure.

These classes together support the core user journey: discovery (User/Movie/Theater), selection (SeatBook with enumerations), and purchase (Booking/Transaction) while keeping each responsibility narrow and clear.

classDiagram
  class User { +int userId +String name +Date dateOfBirth +String mobNo +String emailId +String sex }
  class Movie { +int movieId +int theaterId +MovieType movieType +MovieStatus movieStatus }
  class Theater { +int theaterId +String theaterName +Address address +List<Movie> movies +float rating }
  class Address { +String city +String pinCode +String state +String streetNo +String landmark }
  class Booking { +int bookingId +int userId +int movieId +List<Movie> bookedSeats +int amount +PaymentStatus status_of_payment +Date booked_date +Time movie_timing }
  class Facilities { }
  class SeatBook { +bool seats[] +String place +String ticketType +check_availability() +position_of_seat() +multiple_tickets() +final_booking() }
  class Transaction { +pay(type,seats,place) }
  enum SeatStatus { SEAT_BOOKED; SEAT_NOT_BOOKED }
  enum MovieStatus { Movie_Available; Movie_NotAvailable }
  enum MovieType { ENGLISH; HINDI }
  enum SeatType { NORMAL; EXECUTIVE; PREMIUM; VIP }
  enum PaymentStatus { PAID; UNPAID }
  Theater "1" -- "*" Movie : shows
  User "1" -- "*" Booking : makes
  Booking "1" -- "1" Movie : for
  Booking "1" -- "1" User : by
  Theater "1" -- "1" Address : located_at

4. Activity Diagrams

Activity: Seat Selection & Booking

graph TD
  S1[User selects movie & show] --> S2[Display seat layout]
  S2 --> S3[User picks seats]
  S3 --> S4{All seats available?}
  S4 -- No --> S5[Notify & refresh layout]
  S4 -- Yes --> S6[Lock seats]
  S6 --> S7[Create pending Booking]
  S7 --> S8[Proceed to Payment]

Activity: Payment & Confirmation

graph TD
  P1[Initiate payment] --> P2[Process transaction]
  P2 --> P3{Payment success?}
  P3 -- Yes --> P4[Mark booking PAID]
  P3 -- No --> P5[Release locked seats]
  P4 --> P6[Email/SMS confirmation]
  P5 --> P7[Notify failure]

5. High-Level Code Implementation

Java

enum SeatStatus { SEAT_BOOKED, SEAT_NOT_BOOKED }
enum MovieStatus { Movie_Available, Movie_NotAvailable }
enum MovieType { ENGLISH, HINDI }
enum SeatType { NORMAL, EXECUTIVE, PREMIUM, VIP }
enum PaymentStatus { PAID, UNPAID }

class User { int userId; String name; java.util.Date dateOfBirth; String mobNo; String emailId; String sex; }
class Movie { int movieId; int theaterId; MovieType movieType; MovieStatus movieStatus; }
class Address { String city; String pinCode; String state; String streetNo; String landmark; }
class Theater { int theaterId; String theaterName; Address address; java.util.List<Movie> movies; float rating; }
class Booking { int bookingId; int userId; int movieId; java.util.List<Movie> bookedSeats; int amount; PaymentStatus status_of_payment; java.util.Date booked_date; java.sql.Time movie_timing; }
class Facilities { /* placeholder */ }
class Transaction { void pay(String ticketType, java.util.List<Integer> seatsBooked, String place) {} }
class SeatBook { Transaction transactionObj; boolean[] seats; String place; String ticketType; boolean check_availability(){return true;} int position_of_seat(){return 0;} void multiple_tickets(){} void final_booking(){ transactionObj.pay(ticketType, java.util.Collections.emptyList(), place); } }

Python

from enum import Enum
from datetime import date, time
from typing import List, Optional

class SeatStatus(Enum):
  SEAT_BOOKED = 1
  SEAT_NOT_BOOKED = 2

class MovieStatus(Enum):
  Movie_Available = 1
  Movie_NotAvailable = 2

class MovieType(Enum):
  ENGLISH = 1
  HINDI = 2

class SeatType(Enum):
  NORMAL = 1
  EXECUTIVE = 2
  PREMIUM = 3
  VIP = 4

class PaymentStatus(Enum):
  PAID = 1
  UNPAID = 2

class User:
  def __init__(self, user_id: int, name: str, date_of_birth: date, mob_no: str, email_id: str, sex: str) -> None:
    self.user_id = user_id
    self.name = name
    self.date_of_birth = date_of_birth
    self.mob_no = mob_no
    self.email_id = email_id
    self.sex = sex

class Movie:
  def __init__(self, movie_id: int, theater_id: int, movie_type: MovieType, movie_status: MovieStatus) -> None:
    self.movie_id = movie_id
    self.theater_id = theater_id
    self.movie_type = movie_type
    self.movie_status = movie_status

class Address:
  def __init__(self, city: str, pin_code: str, state: str, street_no: str, landmark: str) -> None:
    self.city = city
    self.pin_code = pin_code
    self.state = state
    self.street_no = street_no
    self.landmark = landmark

class Theater:
  def __init__(self, theater_id: int, theater_name: str, address: Address, rating: float = 0.0) -> None:
    self.theater_id = theater_id
    self.theater_name = theater_name
    self.address = address
    self.movies: List[Movie] = []
    self.rating = rating

class Booking:
  def __init__(self, booking_id: int, user_id: int, movie_id: int, amount: int, status_of_payment: PaymentStatus, booked_date, movie_timing: time) -> None:
    self.booking_id = booking_id
    self.user_id = user_id
    self.movie_id = movie_id
    self.booked_seats: List[int] = []
    self.amount = amount
    self.status_of_payment = status_of_payment
    self.booked_date = booked_date
    self.movie_timing = movie_timing

class Facilities:
  pass

class Transaction:
  def pay(self, ticket_type: str, seats_booked: List[int], place: str) -> None:
    pass

class SeatBook:
  def __init__(self) -> None:
    self.transaction_obj = Transaction()
    self.seats: List[bool] = []
    self.place: str = ""
    self.ticket_type: str = ""
  def check_availability(self) -> bool: return True
  def position_of_seat(self) -> int: return 0
  def multiple_tickets(self) -> None: pass
  def final_booking(self) -> None:
    self.transaction_obj.pay(self.ticket_type, [], self.place)

Movie Booking System Reference

Comments