Project Description: Sales and Invoice Management System Overview This project is a **student-level demo application** developed using **Java** in **NetBeans IDE**, primarily utilizing the **drag-and-drop GUI builder** (JavaFX ). The goal is to create a **desktop-based Sales and Invoice Management System** for a small retail business, helping automate billing, product tracking, and sales reporting. The application replaces the manual process of using notebooks or spreadsheets by providing a **centralized, digital platform** to manage invoices, products, and clients efficiently. --- ## **Key Features** 1. **Login System** * User authentication using username and password. * Different roles (Admin and Staff). * Admin can view analytics and reports, while staff can only create invoices. 2. **Dashboard** * Displays key metrics such as: * Number of products * Total invoices * Total monthly revenue 3. **Product Management** * Add, update, and delete product details (name, price, stock). * Input validation for each field (e.g., correct type and non-empty). 4. **Invoice Management** * Create new invoices with: * Unique system-generated invoice ID. * Client name and date. * Select products and input quantity. * Automatically calculate: * Subtotal * Discounts (fixed or percentage) * Tax * Final total 5. **Invoice Storage and Tracking** * Save invoices using **file I/O** (text files). * View list of all invoices — filter by date or payment status. * Option to mark invoices as **paid** or **unpaid**. * Edit or update invoices if errors are found. 6. **Reporting and Analytics** * Monthly sales summary (total revenue per month). * View unpaid invoices sorted by due date. * Generate bar chart visualization of monthly sales (using **JFreeChart** or JavaFX chart library). * Export monthly reports to text files. * Optionally generate printable **PDF receipts** for customers. --- ## **Technical Details** * **Technology:** Java (JDK 21 preferred) * **IDE:** NetBeans (latest version) * **UI Method:** Drag-and-Drop GUI Builder (JavaFX or Swing) * **Data Storage:** File I/O (text file storage for products, invoices, and clients) * **Libraries Used:** * `JFreeChart` – for visual reports (bar charts) * `java.io` – for file handling (save/load data) * `javafx` or `javax.swing` – for the user interface * **Structure:** * `Main.java` – application entry point * `LoginPage.java` * `Dashboard.java` * `ProductManager.java` * `InvoiceManager.java` * `ReportGenerator.java` * `DataStorage.java` – handles file I/O for products and invoices --- ## **Expected Output** * A **fully functional demo application** that can: * Log in users. * Manage products and invoices. * Calculate totals, discounts, and taxes automatically. * Save and load all data persistently from files. * Show monthly analytics visually. * Export reports and optionally print receipts. --- ## **User Roles** | Role | Permissions | | ----------------- | ------------------------------------------------- | | **Admin** | Full access (create, view analytics, manage data) | | **Staff/Cashier** | Create and update invoices only | --- ## **Development Notes** * Keep the interface clean and simple for demonstration. * Use **drag-and-drop components** for layout design (labels, text fields, buttons, tables, charts). * Implement **basic validation** for all fields (e.g., price must be numeric). * Use clear and well-commented code for student-level readability.