Project Overview

This project was developed during my summer internship in the Enterprise Applications Department. The purpose of the project was to mock a REST API for an Order & Stock Management System.

I used Spring Boot as the main framework and implemented role-based authentication and authorization with Spring Security.

🔑 Key Features

Role-Based Authentication & Authorization

Implemented with Spring Security (JWT).

Two main roles:

ADMIN → Manages products, updates order/return statuses, adjusts stock, and supervises customer operations.

USER → Customers who can place orders, view their own orders, and create return requests only for their own purchases.

Order Management

Customers can place new orders.

Orders go through defined status transitions (Created → Confirmed → Shipped → Delivered → Returned/Cancelled).

Status transitions are validated with a custom validator to ensure correct flow.

Return Management

Users can request returns only for their own orders.

Admin can confirm or reject returns.

On confirmed returns, stock is automatically updated.

Product & Stock Management

Admin can add, update, or delete products.

Stock levels are updated on orders and returns.

Exception Handling

Custom global exception handling for different scenarios (e.g., insufficient stock, unauthorized access, not found errors).

Clear error messages with business-specific error codes.

Metrics & Monitoring

Integrated Spring Boot Actuator for application health and metrics.

Custom metrics added:

Total number of orders

Total number of returns

Total stock quantity across products

Logging

Important business operations (authentication, orders, returns, stock updates) are logged.

Logs can be extended to external systems like MongoDB or ELK Stack for monitoring.

🛠️ Tech Stack

Java 17

Spring Boot

Spring Security (JWT)

Spring Data JPA (Hibernate)

H2 / PostgreSQL (configurable)

Spring Actuator

Lombok

🚀 How It Works

Admin

Manages the catalog and system state.

Updates stock and order statuses.

Confirms or rejects return requests.

User

Registers and logs in.

Places orders and tracks them.

Requests returns for their own orders only.

🤝 Contributing & Feedback

This project will be opened to the public. Feel free to contribute, open pull requests, or report bugs/issues. Any feedback to improve the project is always welcome!

📧 You can also contact me directly for questions or suggestions.