dev.langchain4j.model.LambdaStreamingResponseHandler Maven / Gradle / Ivy

Go to download
package dev.langchain4j.model;

import java.util.function.Consumer;

/**
 * Utility class with lambda-based streaming response handlers.
 *
 * Lets you use Java lambda functions to receive onNext and onError events,
 * from your streaming chat model, instead of creating an anonymous inner class
 * implementing StreamingResponseHandler.
 *
 * Example:
 *  * import static dev.langchain4j.model.LambdaStreamingResponseHandler.*;
 *
 * model.generate("Why is the sky blue?",
 *       onNext(text -> System.out.println(text));
 * model.generate("Why is the sky blue?",
 *       onNext(System.out::println);
 * model.generate("Why is the sky blue?",
 *       onNextAndError(System.out::println, Throwable::printStackTrace));
 * 
 *
 * @param  The type of the response.
 *
 * @see StreamingResponseHandler#onNext(String)
 * @see StreamingResponseHandler#onError(Throwable)
 */
public class LambdaStreamingResponseHandler {
    public static  StreamingResponseHandler onNext(Consumer nextLambda) {
        return new StreamingResponseHandler() {
            @Override
            public void onNext(String text) {
                nextLambda.accept(text);
            }

            @Override
            public void onError(Throwable error) {
                throw new RuntimeException(error);
            }
        };
    }

    public static  StreamingResponseHandler onNextAndError(Consumer nextLambda, Consumer errorLambda) {
        return new StreamingResponseHandler() {
            @Override
            public void onNext(String text) {
                nextLambda.accept(text);
            }

            @Override
            public void onError(Throwable error) {
                errorLambda.accept(error);
            }
        };
    }
}