SQLAuthChatApp

A Java Swing desktop application that combines SQL-based user authentication with a chat-style messaging interface. Built to demonstrate advanced GUI layout techniques, the Strategy design pattern, and JDBC database connectivity.

Features

• Login system with two interchangeable auth backends: in-memory (for testing) and SQL Server via JDBC
• • Custom FormLayout — a hand-written layout manager implementing the Strategy pattern
  • • Chat interface with message bubbles, user avatars, and scroll support
    • • Image utilities for loading, resizing, and rendering avatars

      • • Modular architecture — swap auth providers without changing UI code

        • Tech Stack

        • • Java 17+
          • • Java Swing (BorderLayout, BoxLayout, custom layouts)
            • • JDBC / SQL Server

              • • IntelliJ IDEA

                • Project Structure

                • SQLAuthChatApp/
                  ├── AuthService.java          # Auth interface (Strategy pattern)
                  ├── InMemoryAuthService.java  # Hardcoded credentials for local testing
                  ├── JdbcAuthService.java      # SQL Server login verification via JDBC
                  ├── LoginFrame.java           # Login form UI using FormLayout
                  ├── MChatFrame.java           # Main chat window
                  ├── MessageBubble.java        # Custom chat bubble component
                  ├── FormLayout.java           # Custom Swing layout manager
                  ├── ImageUtil.java            # Avatar loading and resizing utilities
                  └── main.java                 # Entry point
                  

                  Running the App

                  1. Clone the repo
                  2. 2. Open in IntelliJ IDEA
                     3. 3. To use SQL auth: configure your SQL Server connection string in JdbcAuthService.java
                        4. 4. To use in-memory auth: set InMemoryAuthService in main.java

                           5. 5. Run main.java

                              6. Concepts Demonstrated

                              7. • Strategy design pattern for swappable auth providers
                                 • Custom Swing layout manager from scratch
                                 • JDBC connection pooling and prepared statements
                                 • Event-driven GUI with action listeners
                                 • Separation of concerns between UI and business logic