Note0 - Simple Desktop Note-Sharing Application

Note0 is a desktop application built with Java Swing that allows users to register, log in, and share academic materials. This project serves as a foundational example of a database-driven desktop application, demonstrating core concepts of JDBC, secure password handling, file management, and role-based access control without the use of large frameworks like Spring Boot.

All user and material data is stored in a cloud-hosted PostgreSQL database managed by Aiven. Uploaded files are stored on Cloudinary and referenced by secure URLs in the database.

Current Status: Fully functional with core features implemented.

Table of Contents

1. Features
2. Technology Stack
3. How It Works (Application Architecture)
4. Database Schema
5. Getting Started (Setup Guide)
   • Prerequisites
   • Database Setup
   • Configuration
   • Build and Run
6. How to Use the Application

Features

The application currently supports the following features:

✅ User Authentication

• Secure Registration: New users can create an account. Passwords are securely hashed using jBCrypt before being stored.
• User Login: Registered users can log in with their email and password. The system verifies credentials against the hashed passwords in the database.

✅ Material Dashboard

• View Materials: After logging in, users are presented with a dashboard showing all uploaded materials in a sortable table.
• Upload New Materials: Users can upload new files by providing a title, selecting a subject from a dynamic dropdown list, and choosing a file from their computer.
• Open Files: Users can double-click any material in the table to open the associated file using their system's default application.

✅ Interactive Features

• Rating System: Users can select a material from the table and give it a rating from 1 to 5. The average rating is calculated and displayed.
• Search and Filter: The dashboard includes a search bar to filter materials by title and a dropdown menu to filter by subject, allowing for easy navigation.

✅ Admin Functionality

• Role-Based Access: The application distinguishes between USER and ADMIN roles.
• Admin Panel: A special "Admin Panel" button appears on the dashboard only for users logged in with the ADMIN role.
• Subject Management (CRUD): From the admin panel, administrators can Create, Read, Update, and Delete subjects in the database, which dynamically updates the subject dropdowns for all users.

Technology Stack

This project was built from the ground up to demonstrate fundamental Java principles.

Component	Technology	Purpose
Language	Java 17	Core programming language
User Interface	Java Swing	Native desktop GUI toolkit
Database	PostgreSQL (Hosted on Aiven)	Relational database for all data persistence
Build Tool	Apache Maven	Dependency management and project build automation
DB Driver	PostgreSQL JDBC Driver	Translator for communication between Java and PostgreSQL
Security	jBCrypt	A trusted library for secure password hashing

How It Works (Application Architecture)

The project follows a simple, layered architecture to ensure a clear separation of concerns:

• Presentation Layer (RegistrationForm, LoginForm, DashboardForm, AdminForm): These are the Java Swing JFrame classes that the user sees and interacts with. Their only job is to display information and capture user input. They contain no business or database logic.
• Data Access Layer (DAO - UserDAO, MaterialDAO, SubjectDAO): These "Data Access Object" classes are the dedicated workers that handle all communication with the database. They are the only classes that contain SQL code.
• Domain Objects (User, Material, Subject): These are simple POJOs (Plain Old Java Objects) that act as data containers, holding information as it moves between the UI and the DAO layers.
• Database Manager (DatabaseManager.java): A single utility class responsible for establishing the connection to the Aiven database using JDBC.

Database Schema

The application relies on four main tables in the PostgreSQL database:

• users: Stores user information, including id, full_name, email, hashed password, and role.
• subjects: Stores a list of academic subjects, including id and name.
• materials: The central table storing information about each uploaded file, including title, file_path, average_rating, and foreign keys linking to the users and subjects tables.
• ratings: Stores each individual rating, linking a user_id and a material_id with a score.

Getting Started (Setup Guide)

Follow these steps to get the application running on your local machine.

Prerequisites

• Java Development Kit (JDK): Version 17 or newer.
• Apache Maven: Must be installed and configured on your system.
• Aiven Account: A free account with a running PostgreSQL service.

Database Setup

1. Connect to your Aiven PostgreSQL database using a client like DBeaver.
2. Execute the SQL scripts to create the users, subjects, materials, and ratings tables.
3. Manually insert at least one user and change their role to 'ADMIN' for testing purposes.
4. Manually insert a few subjects into the subjects table so the dropdown menus will have options.

Configuration

1. Open the file src/main/java/com/note0/simple/DatabaseManager.java.
2. Replace the placeholder values for DB_URL, USER, and PASSWORD with your actual Aiven credentials.
3. Set the CLOUDINARY_URL (CLOUDINARY_URL="cloudinary://634289314834876:cp8l9KJr4ZQHgVScRjwc3ux-XO8@dje3x3g7p") environment variable before running the app. Format: cloudinary://<api_key>:<api_secret>@<cloud_name>
   • Windows PowerShell example:

     $env:CLOUDINARY_URL = "cloudinary://634289314834876:cp8l9KJr4ZQHgVScRjwc3ux-XO8@dje3x3g7p"
     mvn compile exec:java

   • Windows CMD example:

     set CLOUDINARY_URL=cloudinary://634289314834876:cp8l9KJr4ZQHgVScRjwc3ux-XO8@dje3x3g7p
     mvn compile exec:java

   • macOS/Linux example:

     export CLOUDINARY_URL="cloudinary://634289314834876:cp8l9KJr4ZQHgVScRjwc3ux-XO8@dje3x3g7p"
     mvn compile exec:java

Build and Run

1. Open a terminal or command prompt.
2. Navigate to the root directory of the project (the folder containing pom.xml).
3. Run the following Maven command:

   mvn compile exec:java

4. Maven will compile all the files, and the application's login window will appear.

How to Use the Application

1. Register: Use the "Create New Account" button to register a new user.
2. Log In: Log in with the credentials of a registered user.
3. Use the Dashboard:
   • View existing materials.
   • Use the search and filter options to find specific materials.
   • Double-click a material to open the file.
   • Select a material and click "Rate Selected" to give it a rating.
   • Fill out the form on the left and click "Upload" to add a new material.
4. Admin Functions: If you log in as a user with the ADMIN role, an "Admin Panel" button will appear. Click it to open the subject management window where you can add, edit, or delete subjects.