🎫 THE GATEKEEPER LOGIC - Event Ticketing Platform

Backend Event Ticketing System dengan Java Native + MySQL yang mencegah overselling

Dibuat oleh: Davin Gabriel J
Submission: Backend Web Developer - The Gatekeeper Logic

🎯 Tentang Project

Platform backend untuk sistem tiket event online yang memfasilitasi:

Organizer untuk membuat dan mengelola event
Customer untuk memesan tiket event
Sistem untuk mencegah overselling dengan transaction locking

Problem yang Diselesaikan

Overselling Prevention: Sistem menggunakan Pessimistic Locking untuk memastikan tidak ada tiket yang terjual melebihi kapasitas, bahkan ketika terjadi concurrent requests dari multiple users.

✨ Fitur Utama

🔒 Core Features

CRUD Users - Manajemen data pengguna (Customer & Organizer)
CRUD Events - Buat, update, dan kelola event
CRUD Bookings - Sistem pemesanan tiket
Pessimistic Locking - Mencegah race condition
Transaction Management - ACID compliance
Partial Update - Update field tertentu saja
Status Management - Tracking status booking & event

🛡️ Security Features

Database transaction dengan BEGIN/COMMIT/ROLLBACK
SELECT FOR UPDATE untuk row-level locking
Input validation di Service layer
Error handling yang comprehensive

🏗️ Arsitektur & Database

Struktur Project

src/
├── Main.java                    # Entry point & HTTP Server
├── controllers/
│   ├── UserController.java      # User endpoints
│   ├── EventController.java     # Event endpoints
│   └── BookingController.java   # Booking endpoints
├── services/
│   ├── UserService.java         # Business logic - Users
│   ├── EventService.java        # Business logic - Events
│   └── BookingService.java      # Business logic - Bookings
├── dao/
│   ├── UserDAO.java             # Database access - Users
│   ├── EventDAO.java            # Database access - Events
│   └── BookingDAO.java          # Database access - Bookings
└── models/
    ├── User.java                # User entity
    ├── Event.java               # Event entity
    └── Booking.java             # Booking entity

Database Schema

Table: USERS

CREATE TABLE users (
    id INT AUTO_INCREMENT PRIMARY KEY,
    username VARCHAR(50) UNIQUE NOT NULL,
    email VARCHAR(100) UNIQUE NOT NULL,
    password VARCHAR(255) NOT NULL,
    full_name VARCHAR(100) NOT NULL,
    phone VARCHAR(20),
    role ENUM('CUSTOMER', 'ORGANIZER') DEFAULT 'CUSTOMER',
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

Table: EVENTS

CREATE TABLE events (
    id INT AUTO_INCREMENT PRIMARY KEY,
    organizer_id INT NOT NULL,
    event_name VARCHAR(200) NOT NULL,
    description TEXT,
    event_date DATETIME NOT NULL,
    location VARCHAR(200) NOT NULL,
    total_capacity INT NOT NULL,
    available_tickets INT NOT NULL,
    ticket_price DECIMAL(10,2) NOT NULL,
    status ENUM('ACTIVE', 'CANCELLED', 'COMPLETED') DEFAULT 'ACTIVE',
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
    FOREIGN KEY (organizer_id) REFERENCES users(id)
);

Table: BOOKINGS

CREATE TABLE bookings (
    id INT AUTO_INCREMENT PRIMARY KEY,
    user_id INT NOT NULL,
    event_id INT NOT NULL,
    quantity INT NOT NULL,
    total_price DECIMAL(10,2) NOT NULL,
    status ENUM('PENDING', 'CONFIRMED', 'CANCELLED') DEFAULT 'PENDING',
    booking_date TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
    FOREIGN KEY (user_id) REFERENCES users(id),
    FOREIGN KEY (event_id) REFERENCES events(id)
);

🚀 Cara Install

Prerequisites

Java JDK 11+
MySQL 8.0+
Git

Step 1: Clone Repository

git clone https://github.com/Davin164/BE_Submission_The-Gatekeeper-Logic.git
cd BE_Submission_The-Gatekeeper-Logic

Step 2: Setup Database

# Login ke MySQL
mysql -u root
mysql -u root -p (jika ada password)

# Jalankan database.sql
source database.sql

Step 3: Configure Environment

# Copy .env.example ke .env
cp .env.example .env

# Edit .env sesuai konfigurasi MySQL kamu
nano .env

Isi .env:

DB_HOST=localhost
DB_PORT=3306
DB_NAME=event_ticketing
DB_USER=root
DB_PASSWORD=your_password

Step 4: Compile & Run

# Compile
bash compile.sh

# Run server
bash run.sh

Server akan berjalan di: http://localhost:8080

📚 API Documentation

Base URL

http://localhost:8080/api

👤 USERS ENDPOINTS

1. Get All Users

GET /api/users

Response Success (200):

[
  {
    "id": 1,
    "username": "johndoe",
    "email": "john@example.com",
    "fullName": "John Doe",
    "phone": "081234567890",
    "role": "CUSTOMER",
    "createdAt": "2024-12-24T10:30:00"
  }
]

2. Get User by ID

GET /api/users/{id}

3. Create User

POST /api/users
Content-Type: application/json

Request Body:

{
  "username": "johndoe",
  "email": "john@example.com",
  "password": "password123",
  "fullName": "John Doe",
  "phone": "081234567890",
  "role": "CUSTOMER"
}

Response Success (201):

{
  "id": 1,
  "username": "johndoe",
  "email": "john@example.com",
  "fullName": "John Doe",
  "role": "CUSTOMER"
}

4. Update User

PUT /api/users/{id}
Content-Type: application/json

Request Body (Partial):

{
  "fullName": "John Doe Updated",
  "phone": "081234567999"
}

5. Delete User

DELETE /api/users/{id}

🎪 EVENTS ENDPOINTS

1. Get All Events

GET /api/events

Response Success (200):

[
  {
    "id": 1,
    "organizerId": 1,
    "eventName": "Music Festival 2025",
    "description": "Amazing music festival",
    "eventDate": "2025-06-15T18:00:00",
    "location": "Jakarta Convention Center",
    "totalCapacity": 5000,
    "availableTickets": 4500,
    "ticketPrice": 150000.00,
    "status": "ACTIVE",
    "createdAt": "2024-12-24T10:00:00"
  }
]

2. Get Event by ID

GET /api/events/{id}

3. Create Event

POST /api/events
Content-Type: application/json

Request Body:

{
  "organizerId": 1,
  "eventName": "Music Festival 2025",
  "description": "Amazing music festival",
  "eventDate": "2025-06-15 18:00:00",
  "location": "Jakarta Convention Center",
  "totalCapacity": 5000,
  "ticketPrice": 150000.00
}

Response Success (201):

{
  "id": 1,
  "eventName": "Music Festival 2025",
  "availableTickets": 5000,
  "status": "ACTIVE"
}

4. Update Event

PUT /api/events/{id}
Content-Type: application/json

Request Body (Partial):

{
  "ticketPrice": 120000.00,
  "status": "ACTIVE"
}

5. Delete Event

DELETE /api/events/{id}

🎟️ BOOKINGS ENDPOINTS

1. Get All Bookings

GET /api/bookings

2. Get Booking by ID

GET /api/bookings/{id}

3. Get User Bookings

GET /api/bookings/user/{userId}

4. Get Event Bookings

GET /api/bookings/event/{eventId}

5. Create Booking (WITH LOCKING) 🔒

POST /api/bookings
Content-Type: application/json

Request Body:

{
  "userId": 2,
  "eventId": 1,
  "quantity": 2
}

Response Success (201):

{
  "id": 1,
  "userId": 2,
  "eventId": 1,
  "quantity": 2,
  "totalPrice": 300000.00,
  "status": "PENDING",
  "bookingDate": "2024-12-24T14:30:00"
}

Response Error (400):

{
  "error": "Not enough tickets available"
}

6. Confirm Booking

PUT /api/bookings/{id}/confirm

7. Cancel Booking

PUT /api/bookings/{id}/cancel

8. Delete Booking

DELETE /api/bookings/{id}

🧪 Testing

Testing dengan Thunder Client (VSCode)

Install extension Thunder Client
Import collection atau create new request
Set method dan URL
Untuk POST/PUT, tambahkan body JSON
Klik Send

Testing Script

Gunakan script yang sudah disediakan:

# Test semua endpoints
bash test_api.sh

Manual Testing Examples

Test Overselling Prevention

# Terminal 1: Booking 100 tiket
curl -X POST http://localhost:8080/api/bookings \
  -H "Content-Type: application/json" \
  -d '{"userId": 2, "eventId": 1, "quantity": 100}'

# Terminal 2: Booking 100 tiket (simultaneous)
curl -X POST http://localhost:8080/api/bookings \
  -H "Content-Type: application/json" \
  -d '{"userId": 3, "eventId": 1, "quantity": 100}'

🛠️ Technology Stack

Language: Java (Native) JDK16
Database: MySQL 8.0+
Run API Test: Thunder Client (extension VSCode)

👨‍💻 Author

Davin Gabriel J

GitHub: @Davin164

🙏 Acknowledgments

Submission ini untuk kepentingan Tugas Backend Web Developer GDGoC 2026
Studi Kasus: "The Gatekeeper Logic"
Platform Tiket Event Online dengan Overselling Prevention
Bisa diintegrasikan dengan Spring boot (Framework Java)

Made with ☕ and 💻 in Indonesia Last Updated: 24 December 2025

Name		Name	Last commit message	Last commit date
bin		bin
lib		lib
src		src
.env		.env
.env.example		.env.example
.gitignore		.gitignore
README.md		README.md
compile.sh		compile.sh
database.sql		database.sql
run.sh		run.sh
test_api.sh		test_api.sh

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🎫 THE GATEKEEPER LOGIC - Event Ticketing Platform

🎯 Tentang Project

Problem yang Diselesaikan

✨ Fitur Utama

🔒 Core Features

🛡️ Security Features

🏗️ Arsitektur & Database

Struktur Project

Database Schema

Table: USERS

Table: EVENTS

Table: BOOKINGS

🚀 Cara Install

Prerequisites

Step 1: Clone Repository

Step 2: Setup Database

Step 3: Configure Environment

Step 4: Compile & Run

📚 API Documentation

Base URL

👤 USERS ENDPOINTS

1. Get All Users

2. Get User by ID

3. Create User

4. Update User

5. Delete User

🎪 EVENTS ENDPOINTS

1. Get All Events

2. Get Event by ID

3. Create Event

4. Update Event

5. Delete Event

🎟️ BOOKINGS ENDPOINTS

1. Get All Bookings

2. Get Booking by ID

3. Get User Bookings

4. Get Event Bookings

5. Create Booking (WITH LOCKING) 🔒

6. Confirm Booking

7. Cancel Booking

8. Delete Booking

🧪 Testing

Testing dengan Thunder Client (VSCode)

Testing Script

Manual Testing Examples

Test Overselling Prevention

🛠️ Technology Stack

👨‍💻 Author

🙏 Acknowledgments

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