if (logger.isDebugEnabled()) {
                            logger.debug("Exception in an internal extractor.", e);
                        }
                    }
                }
            }
        } catch (final MessagingException e) {
            if (logger.isDebugEnabled()) {
                logger.debug("Exception in parsing BodyPart.", e);
            }
        }

data/folder/file.html テスト data/file.txt テキスト...

test.tar data/folder/file.html テスト data/file.txt テキスト...

 *   <li>Automatic client initialization</li>
 *   <li>Resource cleanup management</li>
 * </ul>
 *
 */
public class CrawlerClientFactory implements AutoCloseable {
    private static final Logger logger = LogManager.getLogger(CrawlerClientFactory.class);

    /**
     * The crawler container.
     */
    @Resource
    protected CrawlerContainer crawlerContainer;

    /**

 * <ul>
 *   <li>Retry up to 5 times</li>
 *   <li>Wait 500ms between retries</li>
 * </ul>
 *
 */
public class FaultTolerantClient implements CrawlerClient {

    /** Logger instance for this class */
    private static final Logger logger = LogManager.getLogger(FaultTolerantClient.class);

    /** The underlying crawler client */
    protected CrawlerClient client;

    /** Maximum number of retry attempts */

});
```

### Debug Logging

Enable debug logging by adding to your logging configuration:

```xml
<logger name="org.codelibs.fess.crawler" level="DEBUG"/>
<logger name="org.codelibs.fess.crawler.client" level="DEBUG"/>
<logger name="org.codelibs.fess.crawler.extractor" level="DEBUG"/>
```

### Monitoring

```java
// Monitor crawling progress

import org.dbflute.utflute.core.PlainTestCase;

/**
 * @author shinsuke
 *
 */
public class PdfExtractorTest extends PlainTestCase {
    private static final Logger logger = LogManager.getLogger(PdfExtractorTest.class);

    public PdfExtractor pdfExtractor;

    private PdfExtractor pdfExtractorForPdfPassword;

    @Override
    protected void setUp() throws Exception {

    /**
     * Constructs a new FtpAuthenticationHolder.
     */
    public FtpAuthenticationHolder() {
        // Default constructor
    }

    /**
     * Adds an FtpAuthentication object to the holder.
     * @param auth The FtpAuthentication object to add.
     */
    public void add(final FtpAuthentication auth) {
        if (auth != null) {
            authenticationList.add(auth);
        }
    }

 * system.
 *
 * @author shinsuke
 *
 */
public class FileSystemClient extends AbstractCrawlerClient {

    /** Logger instance for this class */
    private static final Logger logger = LogManager.getLogger(FileSystemClient.class);

    /** Key for file attribute view in metadata */
    public static final String FILE_ATTRIBUTE_VIEW = "fileAttributeView";

 *   crawler.addUrl("http://example.com/");
 *   crawler.execute();
 *   crawler.close();
 * </pre>
 */
public class Crawler implements Runnable, AutoCloseable {

    private static final Logger logger = LogManager.getLogger(Crawler.class);

    /**
     * Service for managing URL queues during crawling.
     */
    @Resource
    protected UrlQueueService<UrlQueue<?>> urlQueueService;

    /**