* @param crawlerClientFactory the factory for creating crawler clients
     * @param nThreads the number of threads for the executor service (minimum 1)
     */
    public FileListIndexUpdateCallbackImpl(final IndexUpdateCallback indexUpdateCallback, final CrawlerClientFactory crawlerClientFactory,
            final int nThreads) {

import java.util.HashSet;
import java.util.Set;

import org.codelibs.fess.crawler.builder.RequestDataBuilder;
import org.codelibs.fess.crawler.client.CrawlerClient;
import org.codelibs.fess.crawler.client.CrawlerClientFactory;
import org.codelibs.fess.crawler.container.CrawlerContainer;
import org.codelibs.fess.crawler.entity.RequestData;
import org.codelibs.fess.crawler.entity.ResponseData;
import org.codelibs.fess.crawler.entity.UrlQueue;

import org.codelibs.core.lang.SystemUtil;
import org.codelibs.fess.crawler.builder.RequestDataBuilder;
import org.codelibs.fess.crawler.client.CrawlerClient;
import org.codelibs.fess.crawler.client.CrawlerClientFactory;
import org.codelibs.fess.crawler.container.CrawlerContainer;
import org.codelibs.fess.crawler.entity.AccessResult;
import org.codelibs.fess.crawler.entity.RequestData;
import org.codelibs.fess.crawler.entity.ResponseData;

import org.dbflute.utflute.core.PlainTestCase;

/**
 * @author shinsuke
 *
 */
public class CrawlerClientFactoryTest extends PlainTestCase {
    public CrawlerClientFactory clientFactory;

    @Override
    protected void setUp() throws Exception {
        super.setUp();

├── fess-crawler/              # Core framework
├── fess-crawler-lasta/        # LastaFlute DI integration
└── fess-crawler-opensearch/   # OpenSearch backend
```

### Key Design Patterns

**Factory**: `CrawlerClientFactory`, `ExtractorFactory` - protocol/format-specific component selection
**Strategy**: `CrawlerClient`, `Extractor`, `Transformer` - pluggable implementations
**Builder**: `RequestDataBuilder`, `ExtractorBuilder` - fluent construction

        }

        final CrawlerClientFactory crawlerClientFactory = crawlingConfig.initializeClientFactory(ComponentUtil::getCrawlerClientFactory);
        final CrawlerClient client = crawlerClientFactory.getClient(url);
        if (client == null) {
            throw new CrawlingAccessException(

        }
        final String url = DocumentUtil.getValue(doc, fessConfig.getIndexFieldUrl(), String.class);
        final CrawlerClientFactory crawlerClientFactory =
                config.initializeClientFactory(() -> ComponentUtil.getComponent(CrawlerClientFactory.class));
        final CrawlerClient client = crawlerClientFactory.getClient(url);
        if (client == null) {

	</component>

	<component name="crawlerClientCreator"
		class="org.codelibs.fess.crawler.client.CrawlerClientCreator">
	</component>

	<component name="clientFactory"
		class="org.codelibs.fess.crawler.client.CrawlerClientFactory" instance="prototype">
		<postConstruct name="addClient">
			<arg>["http:.*", "https:.*"]</arg>
			<arg>httpClient</arg>
		</postConstruct>
		<postConstruct name="addClient">
			<arg>"file:.*"</arg>

                })
                .singleton("dataHelper", MemoryDataHelper.class)
                .singleton("robotsTxtHelper", RobotsTxtHelper.class)
                .<CrawlerClientFactory> singleton("clientFactory", CrawlerClientFactory.class, factory -> {
                    factory.addClient("http:.*", container.getComponent("httpClient"));
                    factory.addClient("file:.*", container.getComponent("fsClient"));

    }

    /**
     * Gets the crawler client factory component.
     * @return The crawler client factory.
     */
    public static CrawlerClientFactory getCrawlerClientFactory() {
        return getComponent(CrawlerClientFactory.class);
    }

    /**
     * Gets the crawler client creator component.
     * @return The crawler client creator.
     */