InventoryApp

A Java Servlet-based Inventory Management Web Application using MVC architecture and PostgreSQL

🏪 Inventory Management Web Application

A Java Servlet-based Inventory Management System built using MVC architecture and PostgreSQL.
This project demonstrates real-world use of Servlets, JDBC, and Database Integration in a clean, modular structure.

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🚀 Features

👨‍💻 Role-Based Access

• DEO (Data Entry Operator): Add new products (with supplier validation and unique product IDs).
• POS (Point of Sale Staff): Perform sales, reduce stock, and calculate total price dynamically.
• MGR (Manager): View products with stock levels below 50 for restocking decisions.

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🧩 Tech Stack

Layer	Technology
Frontend	HTML5
Backend	Java Servlets (Jakarta EE)
Database	PostgreSQL
Design Pattern	MVC (Model-View-Controller)
Server	Apache Tomcat 11
Language	Java (JDK 17+)

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🏗️ Project Structure

InventoryApp/
├── src/
│ └── main/
│ ├── java/
│ │ └── com/
│ │ └── company/
│ │ ├── controller/ # Servlets
│ │ ├── dao/ # Data Access Objects
│ │ ├── model/ # Entity Classes
│ │ ├── service/ # Business Logic
│ │ └── util/ # Utilities
│ └── webapp/
│ ├── WEB-INF/
│ │ ├── web.xml # Deployment Descriptor
│ │ └── classes/
│ ├── css/ # Stylesheets
│ ├── js/ # JavaScript files
│ ├── views/ # JSP pages
│ └── index.html # Login Page
├── pom.xml # Maven Configuration
├── README.md
├── .gitignore
└── LICENSE

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💾 Database Setup (PostgreSQL)

CREATE DATABASE Inventory;

\c Inventory;

CREATE TABLE users (
    userid VARCHAR(20) PRIMARY KEY,
    password VARCHAR(50),
    fullname VARCHAR(50),
    role VARCHAR(10) CHECK (role IN ('DEO','POS','MGR'))
);

INSERT INTO users VALUES
('admin','admin123','Administrator','MGR'),
('nish','nish123','The Great Nish','DEO'),
('user1','user123','Sample User 1','POS');

CREATE TABLE supplier (
    supplierid VARCHAR(20) PRIMARY KEY,
    name VARCHAR(50),
    contact VARCHAR(15),
    email VARCHAR(50)
);

CREATE TABLE product (
    productid VARCHAR(20) PRIMARY KEY,
    name VARCHAR(50),
    supplierid VARCHAR(20) REFERENCES supplier(supplierid),
    stockavailable INT,
    openingstock INT,
    lastsupplydate DATE,
    unitprice NUMERIC(10,2)
);

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🧠 Workflow

🔐 Authentication Flow

graph TD
    A[User Access Login Page] --> B[Enter Credentials]
    B --> C{Validation}
    C -->|Invalid| D[Show Error Message]
    C -->|Valid| E{Check User Role}
    E -->|MGR| F[Redirect to Manager Dashboard]
    E -->|DEO| G[Redirect to DEO Dashboard]
    E -->|POS| H[Redirect to POS Dashboard]
    F --> I[Access Manager Features]
    G --> J[Access DEO Features]
    H --> K[Access POS Features]

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1️⃣ Login & Authentication

• User enters credentials on login page
• System validates against database
• Redirects to role-specific dashboard based on user role

2️⃣ DEO (Data Entry Operator)

Main Task: Add Products

• Fill product form with details
• System validates supplier exists
• Checks product ID uniqueness
• Adds product to database
• Updates inventory records

3️⃣ POS (Point of Sale)

Main Task: Process Sales

• Enter product ID to search
• System shows product details & stock
• Enter quantity to sell
• Automatic price calculation
• Stock automatically deducted
• Sales transaction recorded

4️⃣ MGR (Manager)

Main Tasks: Monitor & Analyze

• View low stock alerts (stock < 50)
• Check sales reports and analytics
• Monitor inventory health
• Manage user accounts and roles

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Quick flow

Login → Role Check → Dashboard → Perform Actions → Logout
↓
DEO: Add Products → Validate → Save to DB
POS: Sell Products → Calculate → Update Stock
MGR: View Reports → Analyze → Make Decisions
    

🧠 System Architecture

flowchart TD
    subgraph Frontend
        A[Login Interface]
        B[DEO Dashboard]
        C[POS Dashboard]
        D[Manager Dashboard]
    end

    subgraph Backend
        E[Authentication Service]
        F[Product Service]
        G[Sales Service]
        H[Report Service]
    end

    subgraph Database
        I[Users Table]
        J[Products Table]
        K[Suppliers Table]
        L[Sales Table]
    end

    A --> E
    E --> I
    
    B --> F
    F --> J
    F --> K
    
    C --> G
    G --> J
    G --> L
    
    D --> H
    H --> J
    H --> L
    H --> I

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MVC Architecture

+------------------+        +---------------------+        +--------------------+
|      View        | --->   |      Controller      | --->   |       Model        |
| (JSP/HTML)       |        | (Servlets)           |        | (DAO + Entities)   |
+------------------+        +---------------------+        +--------------------+
        ↑                         ↑                              ↑
        |                         |                              |
+------------------+        +---------------------+        +--------------------+
|   User Interface |        |  Business Logic     |        | Database Layer     |
|   Forms & Pages  |        |  Request Handling   |        | JDBC & SQL         |
+------------------+        +---------------------+        +--------------------+

🚀 Future Enhancements

• 🧩 Role-Based Dashboard UI: Enhance each role (DEO, POS, MGR) with interactive HTML dashboards using AJAX for real-time updates.
• 📦 Sales History Tracking: Maintain a Sales table to store transaction details and generate periodic sales reports.
• 🔔 Low Stock Alerts: Automatically email or notify managers when stock drops below a defined threshold.
• 📊 Analytics Module: Integrate charts (using Chart.js) to visualize sales and stock trends.
• ☁️ Cloud Deployment: Host the application on AWS / Render using PostgreSQL Cloud for real-world scalability.
• 🧠 AI-Powered Stock Prediction: Use a lightweight ML model to forecast product demand and optimize inventory.

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👨‍💻 Author

Nishant (The Great Nish)

• 💼 Developer & Architect of InventoryApp
• 💬 Passionate about Java, AI/ML, and Cybersecurity
• 🌐 GitHub: @nishant-cipher
• 📧 Contact: nishant.cipher@gmail.com

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🪪 License

This project is licensed under the MIT License — you’re free to use, modify, and distribute it with attribution. MIT License Copyright (c) 2025 Nishant