langchain4j-tool-function-calling-patterns

# LangChain4j Tool & Function Calling Patterns Provides patterns for annotating methods as tools, configuring tool executors, registering tools with AI services, validating parameters, and handling tool execution errors in LangChain4j applications. ## Overview LangChain4j uses the `@Tool` annotation to expose Java methods as callable functions for AI agents. The `AiServices` builder registers tools with a chat model, enabling LLMs to perform actions beyond text generation: database queries, API calls, calculations, and business system integrations. Parameters use `@P` for descriptions that guide the LLM. ## When to Use - Building AI agents that call external tools (weather, stocks, database queries) - Defining function specifications for LLM tool use (`@Tool`, `@P` annotations) - Registering and managing tool sets with `AiServices.builder().tools()` - Handling tool execution errors, timeouts, and hallucinated tool names - Implementing context-aware tools that inject user state via `@ToolMemoryId` - Configuring dynamic tool providers for large or conditional tool sets ## Instructions ### 1. Annotate Methods with `@Tool` Define a tool class with methods annotated `@Tool`. Provide a description as the first parameter. Use `@P` for each parameter description. ```java public class WeatherTools { private final WeatherService weatherService; public WeatherTools(WeatherService weatherService) { this.weatherService = weatherService; } @Tool("Get curr...