This repository contains a tutorial on building a retrieval-augmented generation (RAG) chatbot using Java, LangChain4J, and MongoDB Atlas. The application enables querying a knowledge base, retrieving relevant documents, and enhancing responses from a large language model (LLM).

Ensure you have the following installed:

• Java 21 or higher
• Maven (or Gradle, though this tutorial uses Maven)
• A MongoDB Atlas account with an active cluster
• An OpenAI API key

git clone https://github.com/YOUR-USERNAME/rag-tutorial.git
cd rag-tutorial

Create a .env file in the root directory and add the following:

MONGO_URI=<your-mongodb-connection-string>
OPENAI_API_KEY=<your-openai-api-key>

Replace <your-mongodb-connection-string> and <your-openai-api-key> with your actual credentials.

Using Maven:

mvn clean install

mvn exec:java -Dexec.mainClass="com.mongodb.LangChainRagApp"

Alternatively, if using an IDE like IntelliJ IDEA or VS Code, run the main method in LangChainRagApp.java.

This project uses the following dependencies:

<dependencies>  
    <dependency>  
        <groupId>dev.langchain4j</groupId>  
        <artifactId>langchain4j-open-ai</artifactId>  
        <version>1.0.0-alpha1</version>  
    </dependency>  
    <dependency>  
        <groupId>dev.langchain4j</groupId>  
        <artifactId>langchain4j-mongodb-atlas</artifactId>  
        <version>1.0.0-alpha1</version>  
    </dependency>  
    <dependency>  
        <groupId>dev.langchain4j</groupId>  
        <artifactId>langchain4j</artifactId>  
        <version>1.0.0-alpha1</version>  
    </dependency>  
    <dependency>  
        <groupId>com.fasterxml.jackson.core</groupId>  
        <artifactId>jackson-databind</artifactId>  
        <version>2.18.1</version>  
    </dependency>  
</dependencies>

Once the application is running, you can test it by querying the chatbot with:

How does Atlas Vector Search work?

The chatbot will retrieve relevant documents and generate a response using GPT-4.

• Ensure your MongoDB Atlas cluster is running and accessible.
• Verify that your OpenAI API key is valid.
• Check that you have Java 21 or higher installed by running java -version.
• If you encounter dependency issues, try running:

  mvn clean install -U

Feel free to open an issue or submit a pull request for improvements!