Interface RetrievalAugmentor

All Known Implementing Classes:

DefaultRetrievalAugmentor

public interface RetrievalAugmentor

Augments the provided ChatMessage with retrieved Contents.
This serves as an entry point into the RAG flow in LangChain4j.
You are free to use the default implementation (DefaultRetrievalAugmentor) or to implement a custom one.

See Also:

• DefaultRetrievalAugmentor

Method Summary

Modifier and Type	Method	Description
AugmentationResult	augment(AugmentationRequest augmentationRequest)	Augments the ChatMessage provided in the AugmentationRequest with retrieved Contents.
default CompletableFuture<AugmentationResult>	augmentAsync(AugmentationRequest augmentationRequest)	Non-blocking counterpart of augment(AugmentationRequest), invoked by the asynchronous (CompletableFuture/CompletionStage) and reactive (Flow.Publisher) AI Service modes so the RAG flow never blocks the calling thread.

Method Details

augment

AugmentationResult augment(AugmentationRequest augmentationRequest)

Augments the ChatMessage provided in the AugmentationRequest with retrieved Contents.

Parameters:

augmentationRequest - The AugmentationRequest containing the ChatMessage to augment.

Returns:

The AugmentationResult containing the augmented ChatMessage.

augmentAsync

@Experimental
default CompletableFuture<AugmentationResult> augmentAsync(AugmentationRequest augmentationRequest)

Non-blocking counterpart of augment(AugmentationRequest), invoked by the asynchronous (CompletableFuture/CompletionStage) and reactive (Flow.Publisher) AI Service modes so the RAG flow never blocks the calling thread.

The default returns a failed future carrying AsyncNotSupportedException: an augmentor that is not genuinely asynchronous does not pretend to be. DefaultRetrievalAugmentor overrides this to compose its steps into a real future. A custom augmentor that has not opted in is still usable from the non-blocking modes: the AI Service offloads its blocking augment(AugmentationRequest) to a shared virtual-thread executor, rather than the augmentor being silently offloaded on every call.

An implementation that honors cancellation should abort in-flight work when the returned future is cancelled (best-effort).

Parameters:

augmentationRequest - The AugmentationRequest containing the ChatMessage to augment.

Returns:

A CompletableFuture of the AugmentationResult containing the augmented ChatMessage.

Since:

1.20.0