}

            // Add fields
            dataMap.put(fessConfig.getIndexFieldId(), crawlingInfoHelper.generateId(dataMap));

            final String url = dataMap.get(fessConfig.getIndexFieldUrl()).toString();

            if (fessConfig.getIndexerClickCountEnabledAsBoolean()) {
                addClickCountField(dataMap, url, fessConfig.getIndexFieldClickCount());
            }

        IndexUpdateCallback callback = new IndexUpdateCallback() {
            @Override
            public void store(DataStoreParams paramMap, Map<String, Object> dataMap) {
                assertNotNull(paramMap);
                assertNotNull(dataMap);
                assertTrue(dataMap.isEmpty());
                storeCount.incrementAndGet();
            }

            @Override
            public long getDocumentSize() {

        method.setAccessible(true);

        Map<String, String> dataMap = new HashMap<>();
        dataMap.put("key1", "value1");
        dataMap.put("key2", "");
        dataMap.put("key3", null);

        // Test with existing value
        String result1 = (String) method.invoke(crawler, dataMap, "key1", "default");
        assertEquals("value1", result1);

        // Test with empty value

        String[] sitemaps = new String[] { "http://example.com/sitemap.xml", "http://test.com/sitemap.xml" };
        crawlerContext.addSitemaps(sitemaps);

        // Remove and verify
        String[] removedSitemaps = crawlerContext.removeSitemaps();
        assertNotNull(removedSitemaps);
        assertEquals(2, removedSitemaps.length);
        assertEquals("http://example.com/sitemap.xml", removedSitemaps[0]);

    controller.setDefaultIntervalTime(1000);
});
```

### Sitemap Support

```java
// Enable sitemap processing
container.singleton("sitemapsRule", SitemapsRule.class, rule -> {
    rule.addRule("url", ".*sitemap.*");
});

// Add sitemap URL
crawler.addUrl("https://example.com/sitemap.xml");
```

## Data Access and Storage

### Accessing Crawled Data

```java

            Map<String, Object> dataMap = new HashMap<>();
            if (responseData != null) {
                dataMap.put("url", responseData.getUrl());
            }
            dataMap.put("content", "test content");
            resultData.setData(dataMap.toString().getBytes());
            return resultData;
        }

        @Override

        private final long startTime = System.currentTimeMillis();

        @Override
        public void store(DataStoreParams paramMap, Map<String, Object> dataMap) {
            documentCount.incrementAndGet();
        }

        @Override
        public long getDocumentSize() {
            return documentCount.get();
        }

        @Override

func (s *erasureSets) getDiskMap() map[Endpoint]StorageAPI {
	diskMap := make(map[Endpoint]StorageAPI)

	s.erasureDisksMu.RLock()
	defer s.erasureDisksMu.RUnlock()

	for i := range s.setCount {
		for j := 0; j < s.setDriveCount; j++ {
			disk := s.erasureDisks[i][j]
			if disk == OfflineDisk {
				continue
			}
			if !disk.IsOnline() {
				continue
			}
			diskMap[disk.Endpoint()] = disk
		}
	}
	return diskMap

	}

	disks := strings.Split(r.Form.Get("disks"), ",")
	byDisk := strings.EqualFold(r.Form.Get("by-disk"), "true")
	var diskMap map[string]struct{}
	if len(disks) > 0 && disks[0] != "" {
		diskMap = make(map[string]struct{}, len(disks))
		for _, k := range disks {
			if k != "" {
				diskMap[k] = struct{}{}
			}
		}
	}
	jobID := r.Form.Get("by-jobID")

	hosts := strings.Split(r.Form.Get("hosts"), ",")

                    rule.setResponseProcessor(container.getComponent("sitemapsResponseProcessor"));
                    rule.setRuleId("sitemapsRule");
                    rule.addRule("url", ".*sitemap.*");
                })//
                .<DefaultResponseProcessor> singleton("defaultResponseProcessor", DefaultResponseProcessor.class, processor -> {