* It defines the basic structure and configuration options for crawler clients.
 */
public abstract class AbstractCrawlerClient implements CrawlerClient {

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

    /** The MIME type for application/octet-stream. */
    protected static final String APPLICATION_OCTET_STREAM = "application/octet-stream";

 * governing permissions and limitations under the License.
 */
package org.codelibs.fess.crawler.client.http;

import org.codelibs.fess.crawler.client.AbstractCrawlerClient;

/**
 * HcHttpClient is the abstract base class for HTTP client implementations
 * using Apache HttpComponents. This class provides common constants and
 * configurations shared between HC4 and HC5 implementations.

- **Strategy**: `CrawlerClient`, `Extractor`, `Transformer` - pluggable implementations
- **Builder**: `RequestDataBuilder`, `ExtractorBuilder` - fluent construction
- **Template Method**: `AbstractCrawlerClient`, `AbstractExtractor` - common logic with overrides
- **DI**: LastaFlute container with `@Resource` and XML config

### Core Principles