Java 애플리케이션에 LLM 통합을 간소화하는 LangChain4j 소개

<properties>
  <langchain4j.version>0.34.0</langchain4j.version>
</properties>

<dependencies>
  <dependency>
    <groupId>dev.langchain4j</groupId>
    <artifactId>langchain4j-open-ai</artifactId>
    <version>${langchain4j.version}</version>
  </dependency>
</dependencies>

static String getOpenAiApiKey() {
  String apiKey = System.getenv(API_KEY_ENV_NAME);
  if (apiKey == null || apiKey.isEmpty()) {
    Logger.warn("Please provide your own key instead using [{}] env variable", API_KEY_ENV_NAME);
    return "demo";
  }
  return apiKey;
}

ChatLanguageModel model = OpenAiChatModel.withApiKey(getOpenAiApiKey());

String answer = model.generate("Who is Thomas Pesquet?");
Logger.info("Answer is: {}", answer);

Thomas Pesquet is a French aerospace engineer, pilot, and European Space Agency astronaut.
He was selected as a member of the European Astronaut Corps in 2009 and has since completed 
two space missions to the International Space Station, including serving as a flight engineer 
for Expedition 50/51 in 2016-2017. Pesquet is known for his contributions to scientific 
research and outreach activities during his time in space.

<dependency>
  <groupId>dev.langchain4j</groupId>
  <artifactId>langchain4j</artifactId>
  <version>${langchain4j.version}</version>
</dependency>

interface Assistant {
  String chat(String userMessage);
}

Assistant assistant = AiServices.create(Assistant.class, model);

String answer = assistant.chat("Who is Thomas Pesquet?");
Logger.info("Answer is: {}", answer);

interface Assistant {
  @SystemMessage("Please answer in a funny way.")
  String chat(String userMessage);
}

Ah, Thomas Pesquet is actually a super secret spy disguised as an astronaut! 
He's out there in space fighting aliens and saving the world one spacewalk at a time. 
Or maybe he's just a really cool French astronaut who has been to the International 
Space Station. But my spy theory is much more exciting, don't you think?

<dependency>
  <groupId>dev.langchain4j</groupId>
  <artifactId>langchain4j-ollama</artifactId>
  <version>${langchain4j.version}</version>
</dependency>

<dependency>
  <groupId>org.testcontainers</groupId>
  <artifactId>ollama</artifactId>
  <version>1.20.1</version>
  <scope>test</scope>
</dependency>

static String MODEL_NAME = "mistral";
static String DOCKER_IMAGE_NAME = "langchain4j/ollama-" + MODEL_NAME + ":latest";

static OllamaContainer ollama = new OllamaContainer(
  DockerImageName.parse(DOCKER_IMAGE_NAME).asCompatibleSubstituteFor("ollama/ollama"));

@BeforeAll
public static void setup() {
  ollama.start();
}

@AfterAll
public static void teardown() {
  ollama.stop();
}

OllamaChatModel model = OllamaChatModel.builder()
  .baseUrl(ollama.getEndpoint())
  .modelName(MODEL_NAME)
  .build();

Oh, Thomas Pesquet, the man who single-handedly keeps the French space program running 
while sipping on his crisp rosé and munching on a baguette! He's our beloved astronaut 
with an irresistible accent that makes us all want to learn French just so we can 
understand him better. When he's not floating in space, he's probably practicing his 
best "je ne sais quoi" face for the next family photo. Vive le Thomas Pesquet! 
🚀🌍🇫🇷 #FrenchSpaceHero

Oh, you're asking about this legendary figure from history, huh? Well, let me tell 
you a hilarious tale! He was actually born on Leap Year's Day, but only every 400 
years! So, do the math... if we count backwards from 2020 (which is also a leap year), 
then he was born in... *drumroll please* ...1600! Isn't that a hoot? But remember 
folks, this is just a joke, and historical records may vary.

ChatMemory chatMemory = MessageWindowChatMemory.withMaxMessages(10);
Assistant assistant = AiServices.builder(Assistant.class)
  .chatLanguageModel(model)
  .chatMemory(chatMemory)
  .build();

Oh, Thomas Pesquet, the man who was probably born before sliced bread but after dinosaurs! 
You know, around the time when people started putting wheels on suitcases and calling it 
a revolution. So, roughly speaking, he came into this world somewhere in the late 70s or 
early 80s, give or take a year or two - just enough time for him to grow up, become an 
astronaut, and make us all laugh with his space-aged antics! Isn't that a hoot? 
*laughs maniacally*