🦆 Duck Social Network

An interactive social network, built with Java and JavaFX, dedicated to the interaction between People and... Ducks! The project demonstrates the application of advanced Object-Oriented Programming (OOP) concepts, Design Patterns, Graph Algorithms, and relational databases.

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🌟 Main Features

• Dual User System: Supports two types of entities - People (Persoane) and Ducks (Rațe) (with specific abilities like FLYING, SWIMMING, or both).
• Friendship Management: Full system for sending, accepting, or rejecting friend requests.
• Private Messaging (Chat): Real-time chat system (updated via the Observer Pattern), supporting the Reply functionality and keeping track of read/unread messages.
• Events and Competitions: Users can create events (e.g., duck races), register as spectators or participants, and the system automatically generates race times and rankings.
• Advanced Algorithms: Implementation of graph algorithms (DFS/BFS) to identify the number of communities (connected components) and determine the most sociable community.
• Custom Pagination: A pagination system developed from scratch, optimized for large databases, with a responsive graphical interface.
• Graphical User Interface (GUI): Modern UI built with JavaFX, FXML, and styled using CSS.

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🛠️ Technologies and Architecture

This project was developed with a strong focus on Clean Code and a layered architecture.

• Backend: Java 17+
• Frontend (GUI): JavaFX (FXML, CSS)
• Database: PostgreSQL
• DB Communication: JDBC (with PreparedStatement to prevent SQL Injections)
• Security: Password encryption (AES/BCrypt)
• Design Patterns used:
  • Factory Pattern: For dynamic instantiation of different duck types.
  • Decorator Pattern: For adding specific behaviors (FlyingDuck, SwimmingDuck) at runtime.
  • Observer Pattern: To ensure the reactive architecture of the graphical interface (the UI updates automatically upon receiving a new message).
  • Repository / DAO Pattern: For decoupling business logic from data access.

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⚙️ How to run the project locally

If you want to test the application on your own computer, follow the steps below.

1. Prerequisites

• Java Development Kit (JDK): Version 17 or newer.
• PostgreSQL: Installed and running on the default port 5432.
• IDE: IntelliJ IDEA (recommended) or Eclipse, configured for JavaFX/Maven projects.

2. Database Setup

The application requires a PostgreSQL database to run. I have prepared an initialization script that creates the tables, ENUM types, and inserts some mock data.

1. Open pgAdmin (or the psql terminal).
2. Create an empty database named useri.
3. Run the init_db.sql script located in the root of this repository.

3. Environment Variables (Optional, but recommended)

For security reasons, the application reads the database credentials from environment variables. If they are not set, it will fallback to the default values (postgres / postgres).

If your local database has a different password, set the following environment variables in your system or in your IDE's Run Configuration:

• DB_URL (e.g., jdbc:postgresql://localhost:5432/useri)
• DB_USER (e.g., postgres)
• DB_PASSWORD (your PostgreSQL password)

4. Launching the Application

To start the application with the graphical interface, run the main class: src/main/java/org/example/ducksocialnetworkm/Main.java

Note for testing: You can use the following test accounts included in the SQL script:

• Username: MARIAC | Password: MYPASS
• Username: DANV | Password: DANPASS (Note: Make sure the passwords in your local database match the encryption algorithm in the source code).

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📂 Project Structure

The project is organized into packages following the Separation of Concerns principle:

• controller/ - Contains the JavaFX classes that handle UI events.
• depozit/ - Implementation of the Repository pattern for data access (DB). It also contains the paging subpackage for pagination logic.
• domeniu/ - The core entities of the application (User, Rata, Mesaj, Event), logically organized.
• factory/ - The logic for creating complex objects.
• interfata/ - UI components (for the transition from console to GUI).
• serviciu/ - The Business Logic layer, containing validation algorithms, friendship management, and the community system (Graphs).
• utils/ - Global utilities (password encryption, event types for the Observer pattern).
• resources/ - The .fxml and style.css files for the application's appearance.

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🚀 Future Plans (Roadmap)

• Extract hardcoded texts into an internationalization (i18n) system.
• Transition to a Connection Pool (e.g., HikariCP) to optimize database connections.
• Implement a "Dark Mode" by manipulating the CSS file.