final Rule rule = mock(Rule.class);
        final ResponseProcessor responseProcessor = mock(ResponseProcessor.class);

        when(ruleManager.getRule(responseData)).thenReturn(rule);
        when(rule.getRuleId()).thenReturn("test-rule");
        when(rule.getResponseProcessor()).thenReturn(responseProcessor);

        // Use reflection to access protected method

            responseData.setRuleId(rule.getRuleId());
            final ResponseProcessor responseProcessor = rule.getResponseProcessor();
            if (!(responseProcessor instanceof DefaultResponseProcessor)) {
                throw new CrawlingAccessException("The response processor is not DefaultResponseProcessor. responseProcessor: "
                        + responseProcessor + ", url: " + url);
            }

        assertNotNull(processor);
    }

    public void test_implementsResponseProcessor() {
        // Test that NullResponseProcessor implements ResponseProcessor
        NullResponseProcessor processor = new NullResponseProcessor();
        assertTrue(processor instanceof ResponseProcessor);
    }

    public void test_processWithValidResponseData() {
        // Test process method with valid ResponseData

        assertNotNull(proc);
    }

    public void test_implementsResponseProcessor() {
        // Test that SitemapsResponseProcessor implements ResponseProcessor
        assertTrue(processor instanceof ResponseProcessor);
    }

    public void test_processSingleSitemap() {
        // Setup
        ResponseData responseData = new ResponseData();

            } else {
                responseData.setRuleId(rule.getRuleId());
                final ResponseProcessor responseProcessor = rule.getResponseProcessor();
                if (responseProcessor instanceof DefaultResponseProcessor) {
                    final Transformer transformer = ((DefaultResponseProcessor) responseProcessor).getTransformer();
                    final ResultData resultData = transformer.transform(responseData);

**Implementations**:
- `UrlQueueServiceImpl`, `DataServiceImpl`: In-memory (default)
- `OpenSearchDataService`: OpenSearch backend (persistent)

### Processing Pipeline

```
CrawlerThread → Client → ResponseProcessor → Transformer → Extractor → ExtractData
                                                                            ↓
                         ← UrlQueueService ← ← ← ← ← ← ← ← ← ← ← ← ← ← ← ←

        final ResponseData responseData = (ResponseData) objs[2];
        // Rule rule = (Rule) objs[3];
        if (logger.isDebugEnabled()) {
            logger.debug("No ResponseProcessor for ({}, {}). PLEASE CHECK YOUR CONFIGURATION.", responseData.getUrl(),
                    responseData.getMimeType());
        }
    }

    /**
     * Processes finished thread log events.
     *