🤖 AI Chat Service laboration

A Spring Boot lab of a middleware service bridging users and LLMs.

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Overview

AI Chat Service acts as a smart bridge between your frontend and LLM providers. It manages AI personalities, maintains per-session conversation memory, and exposes a clean REST API for chat interactions — all with built-in resilience via automatic retry.

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Features

Feature	Description
🤖 Multiple AI Personalities	Switch between Assistant, Coder, and Riddler
💾 Session-Based Memory	Automatic conversation context management
🔄 Automatic Retry	Exponential backoff for resilience
📚 OpenAPI / Swagger UI	Interactive API documentation out of the box

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Prerequisites

• Java 21+ (tested with Java 25)
• Maven 3.6+
• OpenRouter API key → Get one here

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Getting Started

1. Configure your API key

In IntelliJ IDEA:

1. Go to Run → Edit Configurations...
2. Select AiLabApplication
3. Under Environment Variables, add:

   OPENROUTER_API_KEY=your-api-key-here
   

4. Click Apply → OK

2. Run the application

Open AiLabApplication.java and click Run

The application starts on http://localhost:8080

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Usage

🖥️ Chat Interface (AI created)

http://localhost:8080/

Browser-based chat UI with automatic session management.

📖 Swagger UI

http://localhost:8080/swagger-ui/index.html

Interactive API documentation with a built-in test interface.

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API Reference

POST /api/v1/chat

Request

{
  "personality": "coder",
  "messages": "How do I write a for-loop in Java?"
}

Response

{
  "reply": "A for-loop in Java looks like this: for(int i=0; i<10; i++){}",
  "sessionId": "abc-123-def-456"
}

Personality Options

Value	Behavior
assistant	Helpful general-purpose assistant
coder	Programming teacher
riddler	Responds with riddles

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Project Structure

ai-lab/
├── src/main/java/org/example/ailab/
│   ├── controller/          # REST controllers
│   ├── service/             # Business logic & AI client
│   ├── dto/                 # Data transfer objects
│   ├── configuration/       # Spring configuration
│   └── exception/           # Global exception handler
├── src/main/resources/
│   ├── application.properties  # App configuration
│   └── static/              # Web files (index.html)
└── src/test/java/           # Tests