Code for the Restaurant Management System

We've covered different aspects of the restaurant management system and observed the attributes attached to the problem using various UML diagrams. Let us now explore the more practical side of things, where we will work on implementing the restaurant management system using multiple languages. This is usually the last step in an object-oriented design interview process.

We have chosen the following languages to write the skeleton code of the different classes present in the RMS:

Java
C#
Python
C++
JavaScript

Restaurant management system classes#

In this section, we will provide the skeleton code of the classes designed in the class diagram lesson.

Note: For simplicity, we are not defining getter and setter functions. The reader can assume that all class attributes are private and accessed through their respective public getter methods and modified only through their public method functions.

Enumerations and custom data type#

The following code provides the definition of the enumeration and custom data type used in the restaurant management system.

PaymentStatus: This enumeration keeps track of an order's payment status by the customer.

TableStatus: This enumeration keeps track of the table’s status.

SeatType: This enumeration represents the type of seat for a customer.

AccountStatus: This enumeration keeps track of an account's status.

OrderStatus: This enumeration keeps the customer's order status in check.

ReservationStatus: This enumeration represents the reservation status of a table.

Address: This custom datatype represents the address of the restaurant's branch or a person.

Note: JavaScript does not support enumerations, so we will be using the Object.freeze() method as an alternative. This freezes an object and prevents further modifications.

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Definition of enums and custom datatype

Account and person#

The Account class represents a user account that has an ID, address, status, and a password that can be reset and is validated using the resetPassword() function.

The Person class stores the personal details of a person who can either be an Employee or a Customer of the restaurant. The derived class Employee is further extended by the following:

Receptionist: Has a method named createReservation() to create reservations for customers
Manager: Has a method named addEmployee() to hire new employees to the restaurant
Chef: Has a method named prepareOrder() for preparing the order
Waiter: Has a method named takeOrder() for taking new orders

The derived Customer class has a private member that stores the last visited date of the customer. The definitions of these classes are provided below:

public class Account {
  private String accountId;
  private String password;
  private Address address;
  private AccountStatus status;
  public boolean resetPassword();
}
public abstract class Person {
  private String name;
  private String email;
  private String phone; 
}
public abstract class Employee extends Person {
  private int employeeID;
  private Date dateJoined;
  private Account account;
}
public class Customer extends Person {
  private Date lastVisitedDate;
}
public class Receptionist extends Employee {
  public boolean createReservation();
}
public class Manager extends Employee {
  public boolean addEmployee();

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Account, Person, and its derived classes

public class Table {
  private int tableID;
  private TableStatus status;
  private int maxCapacity;
  private int locationIdentifier;
  private List<TableSeat> seats;
  public boolean isTableFree();
  public boolean addReservation();
  public static List<Table> search(int capacity, Date startTime);
}
public class TableSeat {
  private int tableSeatNumber;
  private SeatType type;
  public boolean updateSeatType(SeatType type);
}

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The Table and TableSeat classes

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The Meal and MealItem classes

public class Menu {
  private int menuID;
  private String title;
  private String description;
  private double price;
  private List<MenuSection> menuSections;
  public boolean addMenuSection(MenuSection menuSection);
  public boolean print();
}
public class MenuSection {
  private int menuSectionID;
  private String title;
  private String description;
  private List<MenuItem> menuItems;
  public boolean addMenuItem(MenuItem menuItem);
}
public class MenuItem {
  private int menuItemID;
  private String title;
  private String description;
  private double price;
  public boolean updatePrice(double price);
}

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The Menu, MenuSelection, and MenuItem classes

Order, kitchen, and reservation#

An Order has a number of meals and is assigned to a waiter and chef for a specific table. Meals can be updated in an Order using the addMeal() and removeMeal() methods.

A Kitchen has a number of chefs where new chefs can be assigned using the assignChef() method.

The Reservation class represents the reservation of a table that stores the reservation time, people count, status, check-in time, and customer information. It also maintains a list of notifications for the customer.

The definitions of these classes are provided below:

public class Order {
  private int OrderID;
  private OrderStatus status;
  private Date creationTime;
  private Meal[] meals;
  private Table table;
  private Waiter waiter;
  private Chef chef;
  public boolean addMeal(Meal meal);
  public boolean removeMeal(Meal meal);
}
public class Kitchen {
  private String name;
  private Chef[] chefs;
  public boolean assignChef();
}
public class Reservation {
  private int reservationID;
  private Date timeOfReservation;
  private int peopleCount;
  private ReservationStatus status;
  private String notes;
  private Date checkInTime;
  private Customer customer;
  private Table[] tables;
  private List<Notification> notifications;
  

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The Order, Kitchen, and Reservation classes

// Payment is an abstract class
public abstract class Payment {
    private int paymentID;
    private Date creationDate;
    private double amount;      
    private PaymentStatus status;
    public abstract void initiateTransaction();
}
public class Check extends Payment {
    private String bankName;
    private String checkNumber;
    public void initiateTransaction() {
        // functionality 
    }
}
public class CreditCard extends Payment {
    private String nameOnCard;
    private int zipcode;
    public void initiateTransaction() {
        // functionality 
    }
}
public class Cash extends Payment {
    private double cashTendered;

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Payment and its derived classes

// Notification is an abstract class
public abstract class Notification {
    private int notificationId;
    // The Date data type represents and deals with both date and time.
    private Date createdOn;      
    private String content;
    public abstract void send(Person person);
}
class SmsNotification extends Notification {
    private String phone;
    public void sendNotification(Person person) {
        // functionality 
    }
}
class EmailNotification extends Notification {
    private String email;
    public void sendNotification(Person person) {
        // functionality 
    }
}

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Notification and its derived classes

public class SeatingChart {
  private int seatingChartID;
  private byte[] seatingChartImage;
  public boolean print();
}
public class Branch {
  private String name;
  private Address location;
  private Kitchen kitchen;
  private Menu menu;
  public Address addseatingChart();
}
public class Restaurant {
  private String name;
  private List<Branch> branches;
  public boolean addBranch(Branch branch);
}

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The SeatingChart, Branch, and Restaurant classes

Restaurant management system classes#

Enumerations and custom data type#

Account and person#

Table and table seat#

Meal and meal item#

Menu, menu section, and menu item#

Order, kitchen, and reservation#

Payment and bill#

Notification#

Seating chart, branch, and restaurant#

Wrapping up#