* Sets the message list for this session.
     *
     * @param messages the messages to set
     */
    public void setMessages(final List<ChatMessage> messages) {
        synchronized (messagesLock) {
            if (messages == null) {
                this.messages = null;
            } else if (messages instanceof CopyOnWriteArrayList) {
                this.messages = messages;
            } else {

     * Gets the messages in this request.
     *
     * @return the list of messages
     */
    public List<LlmMessage> getMessages() {
        return messages;
    }

    /**
     * Sets the messages in this request.
     *
     * @param messages the list of messages
     */
    public void setMessages(final List<LlmMessage> messages) {
        this.messages = messages;
    }

    /**
     * Gets the model name.

        assertEquals(1, session.getMessages().size());
        assertEquals("Hello", session.getMessages().get(0).getContent());
        assertTrue(session.getLastAccessedAt().isAfter(beforeAdd) || session.getLastAccessedAt().isEqual(beforeAdd));
    }

    @Test
    public void test_addMessageWithNullMessages() {
        final ChatSession session = new ChatSession();
        session.setMessages(null);

        messages.add(LlmMessage.user("Message 1"));
        messages.add(LlmMessage.assistant("Message 2"));

        request.setMessages(messages);

        assertSame(messages, request.getMessages());
        assertEquals(2, request.getMessages().size());
    }

    @Test
    public void test_setModel() {
        final LlmChatRequest request = new LlmChatRequest();

                .setLevel(Level.ERROR)
                .setMessage(new SimpleMessage("test message 1"))
                .build();

        LogEvent event2 = Log4jLogEvent.newBuilder()
                .setLoggerName("another.logger.sub")
                .setLevel(Level.ERROR)
                .setMessage(new SimpleMessage("test message 2"))
                .build();

        assertEquals(4, request.getMessages().size());
        assertEquals("Q1", request.getMessages().get(0).getContent());
        assertEquals("A1", request.getMessages().get(1).getContent());
        assertEquals("Q2", request.getMessages().get(2).getContent());
        assertEquals("A2", request.getMessages().get(3).getContent());
    }

    @Test

        return Log4jLogEvent.newBuilder() //
                .setLoggerName(loggerName) //
                .setLevel(level) //
                .setMessage(new SimpleMessage(message)) //
                .setTimeMillis(System.currentTimeMillis()) //
                .build();
    }

    @Test
    public void test_createAppender() {

            return null;
        }
        session.touch();
        if (logger.isDebugEnabled()) {
            logger.debug("Session retrieved. sessionId={}, messageCount={}", sessionId, session.getMessages().size());
        }
        return session;
    }

    /**
     * Gets or creates a session.
     *
     * @param sessionId the session ID (can be null to create a new session)

        final String llmType = getLlmType();
        if (logger.isDebugEnabled()) {
            logger.debug("[LLM] Starting LLM chat request. llmType={}, messageCount={}", llmType, request.getMessages().size());
            for (final LlmMessage msg : request.getMessages()) {
                logger.debug("[LLM] message: role={}, content={}", msg.getRole(), msg.getContent());
            }
        }
        try {

            final List<LlmMessage> history = new ArrayList<>();
            for (final ChatMessage msg : session.getMessages()) {
                if (msg.isUser()) {
                    history.add(LlmMessage.user(msg.getContent()));
                } else if (msg.isAssistant()) {
                    final String content =