Langchain4j-03

  
@AiService  
interface Assistant {  
    @SystemMessage("You are a polite assistant")  
    String chat(String userMessage);  
}  
public void chatMeme() {  
    ChatMemory chatMemory = MessageWindowChatMemory.withMaxMessages(10);  
  
    Assistant assistant = AiServices.builder(Assistant.class)  
            .chatModel(qwenChatModel)  
            .chatMemory(chatMemory)  
            .build();  
  
    String answer = assistant.chat("Hello! My name is Klaus.");  
    System.out.println(answer); // Hello Klaus! How can I assist you today?  
  
    String answerWithName = assistant.chat("What is my name?");  
    System.out.println(answerWithName); // Your name is Klaus.  
}

import dev.langchain4j.memory.chat.MessageWindowChatMemory;
import dev.langchain4j.model.chat.ChatModel;
import dev.langchain4j.model.openai.OpenAiChatModel;
import dev.langchain4j.service.AiServices;
import dev.langchain4j.service.MemoryId;
import dev.langchain4j.service.UserMessage;

import static dev.langchain4j.model.openai.OpenAiChatModelName.GPT_4_O_MINI;

public class ServiceWithMemoryForEachUserExample {

    /**
     * See also {@link ServiceWithPersistentMemoryForEachUserExample}.
     */

    interface Assistant {

        String chat(@MemoryId int memoryId, @UserMessage String userMessage);
    }

    public static void main(String[] args) {

        ChatModel model = OpenAiChatModel.builder()
                .apiKey(ApiKeys.OPENAI_API_KEY)
                .modelName(GPT_4_O_MINI)
                .build();

        Assistant assistant = AiServices.builder(Assistant.class)
                .chatModel(model)
                .chatMemoryProvider(memoryId -> MessageWindowChatMemory.withMaxMessages(10))
                .build();

        System.out.println(assistant.chat(1, "Hello, my name is Klaus"));
        // Hi Klaus! How can I assist you today?

        System.out.println(assistant.chat(2, "Hello, my name is Francine"));
        // Hello Francine! How can I assist you today?

        System.out.println(assistant.chat(1, "What is my name?"));
        // Your name is Klaus.

        System.out.println(assistant.chat(2, "What is my name?"));
        // Your name is Francine.
    }
}

class PersistentChatMemoryStore implements ChatMemoryStore {

        @Override
        public List<ChatMessage> getMessages(Object memoryId) {
          // TODO: Implement getting all messages from the persistent store by memory ID.
          // ChatMessageDeserializer.messageFromJson(String) and 
          // ChatMessageDeserializer.messagesFromJson(String) helper methods can be used to
          // easily deserialize chat messages from JSON.
        }

        @Override
        public void updateMessages(Object memoryId, List<ChatMessage> messages) {
            // TODO: Implement updating all messages in the persistent store by memory ID.
            // ChatMessageSerializer.messageToJson(ChatMessage) and 
            // ChatMessageSerializer.messagesToJson(List<ChatMessage>) helper methods can be used to
            // easily serialize chat messages into JSON.
        }

        @Override
        public void deleteMessages(Object memoryId) {
          // TODO: Implement deleting all messages in the persistent store by memory ID.
        }
    }

ChatMemory chatMemory = MessageWindowChatMemory.builder()
        .id("12345")
        .maxMessages(10)
        .chatMemoryStore(new PersistentChatMemoryStore())
        .build();