Room Reservation API

Overview

Room Reservation API is a Spring Boot RESTful application for managing room bookings.
It allows viewing available rooms, creating and canceling bookings, and checking room availability.

Key features include:

• CRUD operations for rooms with filtering, pagination, and sorting.
• Booking management with validation to prevent overlapping bookings.
• Availability checks for rooms in a specified time range.
• DTO-based API responses for clean and safe data transfer.
• Global exception handling with meaningful HTTP status codes.

Technologies & Tools

Programming Languages: Java, SQL
Frameworks & Libraries: Spring Boot, Spring Data JPA, Hibernate, Jakarta Validation
Databases: MySQL Web Development: REST API
Other Tools & Technologies: Git, Maven

Features

Room Management

• Create, update, and delete rooms.
• Filter rooms by availability, location, or name.
• Pagination and sorting by id, name, capacity, or location.

Booking Management

• Create bookings with validation to prevent overlaps.
• Cancel bookings safely.
• Check room availability for a given time period.
• Transactional operations with Serializable isolation to prevent concurrency issues.

API Endpoints

Method	Path	Description	Parameters / Body
GET	/rooms	Get list of rooms	page, size, sortBy, order, available, location, name
POST	/rooms	Create a room	JSON RoomDTO
PUT	/rooms/{id}	Update a room	JSON RoomDTO
DELETE	/rooms/{id}	Delete a room
GET	/bookings	Get bookings with pagination	user, page, size
POST	/bookings	Create a booking	JSON BookingDTO (roomId, user, startTime, endTime)
PUT	/bookings/{id}/cancel	Cancel a booking
GET	/bookings/{id}/availability	Check room availability for a period	startTime, endTime

Architecture & Design

• DTOs (RoomDTO, BookingDTO): Ensure clean API responses without exposing internal models.
• Validation: Input validation via @Valid and Jakarta Validation annotations.
• Error Handling: Global @ControllerAdvice handles exceptions with proper HTTP status codes (400, 404, 409).
• Repository Layer: Spring Data JPA repositories with custom queries for filtering and checking overlaps.
• Concurrency Control: Serializable transactions for safe booking creation and cancellation.

Example Usage

1. Get available rooms with pagination and filtering:
   GET /rooms?page=0&size=5&sortBy=capacity&order=asc&available=true&location=1st%20Floor

2. Check availability for a room: GET /bookings/12/availability?startTime=2025-08-01T10:00&endTime=2025-08-01T12:00

3. Create a booking: POST /bookings { "roomId": 12, "user": "Marko", "startTime": "2025-08-01T10:00", "endTime": "2025-08-01T12:00" }

4. Cancel a booking: PUT /bookings/5/cancel

Why This Project Stands Out

• Strong backend architecture with layered design (Controller → Service → Repository).
• Transactional safety with concurrency handling to prevent double bookings.
• Clean API design using DTOs and pagination/sorting for large datasets.
• Professional error handling with descriptive messages.
• Demonstrates full Java backend skillset: Spring Boot, JPA, validation, REST, exception handling.