Package com.vaadin.flow.component.ai.provider

Class LangChain4JLLMProvider

java.lang.Object

com.vaadin.flow.component.ai.provider.LangChain4JLLMProvider

All Implemented Interfaces:

LLMProvider, Serializable

public class LangChain4JLLMProvider
extends Object
implements LLMProvider

LangChain4j implementation of LLMProvider.

Supports both streaming and non-streaming LangChain4j models. Tool calling is supported through LangChain4j's Tool annotation.

Each provider instance maintains its own chat memory. To share conversation history across components, reuse the same provider instance.

Author:

Vaadin Ltd

See Also:

• Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface com.vaadin.flow.component.ai.provider.LLMProvider

LLMProvider.Attachment, LLMProvider.LLMRequest

Constructor Summary

Constructors

Constructor	Description
LangChain4JLLMProvider(dev.langchain4j.model.chat.ChatModel chatModel)	Constructor with a non-streaming chat model.
LangChain4JLLMProvider(dev.langchain4j.model.chat.StreamingChatModel chatModel)	Constructor with a streaming chat model.

Method Summary

Modifier and Type	Method	Description
reactor.core.publisher.Flux<String>	stream(LLMProvider.LLMRequest request)	Streams a response from the LLM based on the provided request.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

LangChain4JLLMProvider

public LangChain4JLLMProvider(dev.langchain4j.model.chat.StreamingChatModel chatModel)

Constructor with a streaming chat model.

Parameters:

chatModel - the streaming chat model, not null

Throws:

NullPointerException - if chatModel is null

LangChain4JLLMProvider

public LangChain4JLLMProvider(dev.langchain4j.model.chat.ChatModel chatModel)

Constructor with a non-streaming chat model.

Parameters:

chatModel - the non-streaming chat model, not null

Throws:

NullPointerException - if chatModel is null

Method Details

stream

public reactor.core.publisher.Flux<String> stream(LLMProvider.LLMRequest request)

Description copied from interface: LLMProvider

Streams a response from the LLM based on the provided request. This method returns a reactive stream that emits response tokens as they become available from the LLM. The provider manages conversation history internally, so each call to this method adds to the ongoing conversation context.

Specified by:

stream in interface LLMProvider

Parameters:

request - the LLM request containing user message, system prompt, attachments, and tools, not null

Returns:

a Flux stream that emits response tokens as strings, never null