*/
    @Override
    public void doFilter(final ServletRequest request, final ServletResponse response, final FilterChain chain)
            throws IOException, ServletException {
        final HttpServletRequest req = (HttpServletRequest) request;
        final HttpServletResponse resp = (HttpServletResponse) response;
        NtlmPasswordAuthentication ntlm = negotiate(req, resp, false);

        if (ntlm == null) {

            final CommonServerMessageBlock response) {
        if (log.isTraceEnabled()) {
            log.trace("Signing with seq " + this.signSequence);
        }

        ((ServerMessageBlock) request).setSignSeq(this.signSequence);
        if (response != null) {
            ((ServerMessageBlock) response).setSignSeq(this.signSequence + 1);
        }

        try {

    }

    /**
     * Helper method to mock the response of an HttpURLConnection.
     */
    private void mockResponse(int code, String message, Map<String, List<String>> headers, InputStream errorStream) throws IOException {
        mockResponse(this.mockConnection, code, message, headers, errorStream);
    }

    /**
     * Helper method to mock the response of a specific HttpURLConnection instance.
     */

    private static final int SMB2_HEADER_LENGTH = 64;

    /**
     * Build a minimal SMB2 header for a response.
     */
    private static byte[] buildSmb2Header() {
        byte[] header = Arrays.copyOf(SMBUtil.SMB2_HEADER, SMBUtil.SMB2_HEADER.length);
        // Mark as server->client response for realism
        SMBUtil.writeInt4(0x00000001, header, 16); // Flags
        // Command SMB2_CREATE (0x0005)

In this case, you could want to document how that external API *should* look like. What *path operation* it should have, what body it should expect, what response it should return, etc.

## An app with callbacks { #an-app-with-callbacks }

Let's see all this with an example.

Imagine you develop an app that allows creating invoices.

    @Override
    public Logger getLogger() {
        return logger;
    }

    /**
     * Gets the appropriate extractor for the given response data.
     * Selects an extractor based on the MIME type or falls back to the Tika extractor.
     *
     * @param responseData the response data containing the document to extract
     * @return the extractor instance for processing the document

{
  "@timestamp": "2099-11-15T14:12:12",
  "http": {
    "request": {
      "method": "get"
    },
    "response": {
      "bytes": 1070000,
      "status_code": 200
    },
    "version": "1.1"
  },
  "message": "GET /search HTTP/1.1 200 1070000",
  "source": {
    "ip": "192.168.0.1"
  },
  "user": {
    "id": "user"
  }

        @Override
        public void process(String origin, ServletRequest request, ServletResponse response) {
            processCalled = true;
            lastOrigin = origin;
            lastRequest = request;
            lastResponse = response;
        }

        public boolean wasProcessCalled() {
            return processCalled;
        }

    }

    @Test
    @DisplayName("Should create correct response")
    void testCreateResponse() {
        // Given
        request = new Smb2NegotiateRequest(mockConfig, 0);

        // When
        Smb2NegotiateResponse response = request.createResponse(mockContext, request);

        // Then
        assertNotNull(response);
        assertTrue(response instanceof Smb2NegotiateResponse);
    }

    @Test

import org.lastaflute.core.message.MessageManager;
import org.lastaflute.core.time.TimeManager;
import org.lastaflute.db.dbflute.accesscontext.AccessContextArranger;
import org.lastaflute.web.TypicalAction;
import org.lastaflute.web.response.ActionResponse;
import org.lastaflute.web.ruts.process.ActionRuntime;
import org.lastaflute.web.servlet.request.RequestManager;
import org.lastaflute.web.servlet.request.ResponseManager;