🚆 Train Booking System (Java CLI Project)

A clean and modular Train Ticket Booking System built in Java using a file-based JSON persistence layer. Designed to demonstrate strong fundamentals in OOP, file handling, CLI-based interaction, password encryption, and service-layer design — all without any external database or UI.

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✨ Key Features

• ✅ User Sign-up & Login (with password hashing using BCrypt)
• ✅ Search trains by source and destination
• ✅ Live seat selection and booking
• ✅ View all personal bookings
• ✅ Cancel ticket by Ticket ID
• ✅ File-based JSON persistence
• ✅ Clean Low-Level Design (LLD) structure with modular services

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🧱 Low-Level Design (LLD Overview)

👤 User

• name (String)
• password (String, stored hashed)
• hashedPassword (String)
• ticketsBooked (List<Ticket>)
• userId (UUID)

🎟️ Ticket

• ticketId (UUID)
• userId (UUID)
• source (String)
• destination (String)
• dateOfTravel (ZonedDateTime)
• train (Train)

🚂 Train

• trainId (String)
• trainNo (String)
• seats (List<List<Integer>> - 2D layout)
• stations (List<String>)
• stationTimes (Map<StationName, Time>)

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🛠 Tech Stack

Component	Technology
Language	Java 21
Build Tool	Gradle
JSON Handling	Jackson + jsr310 (for time)
Password Hash	BCrypt (secure authentication)
Boilerplate	Lombok (getter/setter cleanup)
Data Storage	JSON (no external DB used)

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⚙️ How It Works

🔐 Signup & Login

• Users sign up with a password (hashed before saving).
• On login, password is verified using BCrypt.checkpw().

🔎 Train Search

• Trains are filtered by matching source and destination (in correct order).

💺 Seat Booking

• Available seats are shown in a 2D matrix.
• Seat is marked 1 when booked.

📂 Booking Persistence

• Bookings are saved in users.json.
• Seat availability updates in trains.json.

❌ Cancel Ticket

• User enters ticket ID to cancel.
• Ticket is removed from their booking list.

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🚀 Getting Started

1. Clone the Repository

git clone https://github.com/yourusername/train-booking-java.git
cd train-booking-java