Hotel Reservation Application

A command-line based Hotel Reservation Application built in Java following Object-Oriented Programming (OOP) principles and a layered architecture. The application allows customers to create accounts, search for available rooms, make reservations, and enables administrators to manage rooms, customers, and reservations.

🚀 Features

👤 Customer Features

• Create a customer account
• Search for available rooms
• Reserve a room
• View personal reservations
• Receive recommended room availability if the selected dates are unavailable

🛠️ Admin Features

• View all customers
• View all rooms
• View all reservations
• Add paid or free rooms
• Prevent duplicate room creation

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🏗️ Project Architecture

The application follows a layered architecture to maintain separation of concerns.

Hotel Reservation Application
│
├── UI Layer
│   ├── MainMenu
│   └── AdminMenu
│
├── API Layer
│   ├── HotelResource
│   └── AdminResource
│
├── Service Layer
│   ├── CustomerService
│   └── ReservationService
│
└── Model Layer
    ├── Customer
    ├── IRoom
    ├── Room
    ├── FreeRoom
    ├── Reservation
    └── RoomType

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📁 Project Structure

HotelReservationApplication/
│
├── api/
│   ├── AdminResource.java
│   └── HotelResource.java
│
├── model/
│   ├── Customer.java
│   ├── FreeRoom.java
│   ├── IRoom.java
│   ├── Reservation.java
│   ├── Room.java
│   └── RoomType.java
│
├── service/
│   ├── CustomerService.java
│   └── ReservationService.java
│
├── AdminMenu.java
├── MainMenu.java
└── HotelApplication.java

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💻 Technologies Used

• Java
• Object-Oriented Programming (OOP)
• Collections Framework
• Regular Expressions (Regex)
• Date & Calendar API
• Command Line Interface (CLI)

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📚 OOP Concepts Implemented

• Encapsulation
• Abstraction
• Inheritance
• Polymorphism
• Interfaces
• Singleton Design Pattern
• Layered Architecture

---

📦 Model Classes

Customer

• First Name
• Last Name
• Email Validation using Regex

Room

• Room Number
• Price
• Room Type

FreeRoom

• Extends Room
• Automatically sets room price to 0

Reservation

• Customer
• Room
• Check-in Date
• Check-out Date

RoomType

Enumeration containing:

• SINGLE
• DOUBLE

IRoom

Interface defining room behavior.

---

⚙️ Service Layer

CustomerService

Handles customer-related operations:

• Add customer
• Get customer
• Retrieve all customers

ReservationService

Handles reservation-related operations:

• Add room
• Get room
• Reserve room
• Search available rooms
• Search recommended rooms
• View customer reservations
• Display all reservations

---

🔗 API Layer

HotelResource

Acts as an intermediary between the UI and services.

Functions include:

• Create customer
• Find room
• Reserve room
• Get customer reservations

AdminResource

Provides administrative operations:

• Add rooms
• View all rooms
• View all customers
• View all reservations

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🖥️ User Interface

Main Menu

1. Find and reserve a room
2. See my reservations
3. Create an account
4. Admin
5. Exit

Admin Menu

1. See all Customers
2. See all Rooms
3. See all Reservations
4. Add a Room
5. Back to Main Menu

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✅ Validations Implemented

Customer Validation

• Email format validation using Regular Expressions
• Prevent duplicate customer accounts

Example:

user@example.com

---

Room Validation

• Room number cannot be empty
• Room numbers must be unique
• Room price cannot be negative
• Room type validation (SINGLE or DOUBLE only)

---

Reservation Validation

• Check-in date cannot be in the past
• Check-out date must be after check-in date
• Minimum stay of one day
• Prevent overlapping reservations
• Prevent double booking

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🔍 Room Search

The application searches available rooms based on:

• Check-in Date
• Check-out Date

If rooms are unavailable, the application automatically searches for available rooms 7 days later and recommends them to the user.

Example:

Requested:
10 Apr → 12 Apr

Recommended:
17 Apr → 19 Apr

Users can directly reserve the recommended room.

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🆓 Free Room Support

The application supports free rooms using inheritance.

Features:

• Price automatically set to ₹0
• Displayed as Free
• Available during room searches
• Can be reserved like any other room

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🗂️ Collections Used

Data	Collection
Customers	HashMap
Rooms	HashMap
Reservations	ArrayList

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🧩 Design Patterns Used

Singleton Pattern

Implemented in:

• CustomerService
• ReservationService
• HotelResource
• AdminResource

Ensures only one instance of each service/resource exists throughout the application.

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🛡️ Exception Handling

The application gracefully handles invalid inputs using:

• try-catch blocks
• IllegalArgumentException

Examples:

• Invalid email
• Duplicate room
• Duplicate customer
• Invalid room type
• Invalid reservation dates
• Room already booked

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📋 Sample Workflow

Customer

Create Account
      ↓
Search Rooms
      ↓
Select Room
      ↓
Reserve Room
      ↓
View Reservation

Admin

Login Admin Menu
      ↓
Add Rooms
      ↓
View Customers
      ↓
View Rooms
      ↓
View Reservations

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▶️ How to Run

1. Clone the repository

git clone https://github.com/your-username/hotel-reservation-application.git

2. Open the project in IntelliJ IDEA (or any Java IDE).

3. Run:

HotelApplication.java

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🎯 Learning Outcomes

This project demonstrates practical implementation of:

• Java Fundamentals
• Object-Oriented Programming
• Interfaces and Inheritance
• Polymorphism
• Collections Framework
• Singleton Design Pattern
• Layered Architecture
• Exception Handling
• Input Validation
• Command Line Applications
• Date and Calendar Operations

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📌 Future Improvements

• Database integration (MySQL/PostgreSQL)
• Spring Boot REST API
• Authentication & Authorization
• Room cancellation
• Payment integration
• Room categories and pricing
• JUnit testing
• Logging framework
• File-based or database persistence

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👨‍💻 Author

Ajay

Backend Developer | Java | Spring Boot | SQL

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