Train Management System

A Java application that manages train routes, merging, and station management. The system can create trains, manage their routes, and handle train merging at designated stations.

Features

• 🚂 Train creation and route management
• 🛤️ Dynamic route loading from CSV files
• 🔄 Train merging at designated stations
• 🚉 Station distance and path calculations
• ⚡ Command-based architecture
• 🧪 Comprehensive test coverage

Technology Stack

• Java 11
• Gradle
• JUnit 5
• Mockito

Project Structure

src/
├── main/
│   ├── java/com/geektrust/backend/
│   │   ├── commands/          # Command pattern implementations
│   │   ├── entities/          # Domain models
│   │   ├── repositories/      # Data access layer
│   │   ├── services/         # Business logic
│   │   └── exceptions/       # Custom exceptions
│   └── resources/
│       └── *.csv             # Route configuration files
└── test/
    └── java/com/geektrust/backend/
        ├── commands/          # Command tests
        ├── entities/          # Entity tests
        ├── services/         # Service layer tests
        └── resources/        # Test data files

Getting Started

Prerequisites

• JDK 11 or higher
• Gradle 7.x or higher

Building the Project

# Clone the repository
git clone <repository-url>
cd anantsaini-india-ME_GEEKTRUST_BACKEND

# Build the project
./gradlew build

# Run tests
./gradlew test

Running the Application

# Run with input file
java -jar build/libs/geektrust.jar <path-to-input-file>

Input Format

The application accepts a text file with train configurations. Each line should contain:

TRAIN_NAME ENGINE STATION1 STATION2 ... STATIONN

Example:

TRAIN_A ENGINE NDL NDL GHY NJP NGP
TRAIN_B ENGINE NJP GHY AGA BPL PTA

Output Format

The application will output train arrivals and departures in the format:

ARRIVAL TRAIN_NAME ENGINE STATION1 STATION2 ... STATIONN
DEPARTURE TRAIN_NAME ENGINE1 ENGINE2 STATION1 STATION2 ... STATIONN

Architecture

Key Components

1. Commands

   • LoadRouteCommand: Loads route data from CSV files
   • CreateTrainCommand: Creates new train instances
   • RunTrainTillMergingStationCommand: Handles train movement
   • MergeTrainCommand: Manages train merging operations

2. Services

   • TrainService: Core business logic for train operations
   • RouteService: Route management and calculations

3. Repositories

   • Implements CRUD operations for entities
   • Uses in-memory storage with ICrudRepository interface

4. Entities

   • Train: Represents a train with its units
   • Route: Defines a train route with stations
   • Station: Represents a station with distance info
   • Bogie & Engine: Train unit types

Testing

The project includes comprehensive unit tests for all components:

# Run all tests
./gradlew test

# Run specific test class
./gradlew test --tests "com.geektrust.backend.commands.CreateTrainCommandTest"

# Generate test coverage report
./gradlew jacocoTestReport

Test reports can be found at build/reports/tests/test/index.html.

Design Patterns

• Command Pattern: For executing different train operations
• Repository Pattern: For data access abstraction
• Dependency Injection: For loose coupling between components
• Builder Pattern: For constructing complex objects

Error Handling

The application includes custom exceptions:

• NoEngineFoundException
• RouteNotFoundException
• NoMergingOrDivergingStationFoundOnRouteException

Contributing

1. Fork the repository
2. Create a feature branch
3. Commit your changes
4. Push to the branch
5. Create a Pull Request

License

This project is licensed under the MIT License - see the LICENSE file for details.

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Built with ❤️ for GeekTrust Backend Challenge