fess-crawler-parent/
├── 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

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */
package org.codelibs.core.beans.factory;

import static org.codelibs.core.collection.CollectionsUtil.newConcurrentHashMap;
import static org.codelibs.core.collection.CollectionsUtil.putIfAbsent;
import static org.codelibs.core.misc.AssertionUtil.assertArgumentNotNull;

import java.util.Enumeration;
import java.util.Properties;

import org.apache.maven.cling.logging.impl.UnsupportedSlf4jBindingConfiguration;
import org.slf4j.ILoggerFactory;

/**
 * Slf4jConfiguration factory, loading implementations from <code>META-INF/maven/slf4j-configuration.properties</code>
 * configuration files in class loader: key is the class name of the ILoggerFactory, value is the class name of

          <role-hint>default</role-hint>
          <field-name>logger</field-name>
        </requirement>
        <requirement>
          <role>org.apache.maven.artifact.factory.ArtifactFactory</role>
          <role-hint>default</role-hint>
          <field-name>artifactFactory</field-name>
        </requirement>
        <requirement>

import org.codehaus.plexus.context.Context;
import org.codehaus.plexus.context.ContextException;
import org.codehaus.plexus.personality.plexus.lifecycle.phase.Contextualizable;

/**
 * A conflict resolver factory that obtains instances from a plexus container.
 *
 * TODO you don't need the container in here with the active maps (jvz).
 * @since 3.0
 */
@Named
@Singleton
@Deprecated

  RESTRICTS_KEYS,
  RESTRICTS_VALUES,
  SUPPORTS_PUT,
  SUPPORTS_REMOVE,
  FAILS_FAST_ON_CONCURRENT_MODIFICATION,
  /**
   * Indicates that the constructor or factory method of a map, usually an immutable map, throws an
   * {@link IllegalArgumentException} when presented with duplicate keys instead of discarding all
   * but one.
   */
  REJECTS_DUPLICATES_AT_CREATION,

) : EventSource,
  ServerSentEventReader.Callback,
  Callback {
  private var call: Call? = null

  @Volatile private var canceled = false

  fun connect(callFactory: Call.Factory) {
    call =
      callFactory.newCall(request).apply {
        enqueue(this@RealEventSource)
      }
  }

  override fun onResponse(
    call: Call,
    response: Response,
  ) {

     * that should be registered. The returned collection should contain all the enum values
     * that this provider wants to contribute.
     * <p>
     * The values returned by this method should be created using the appropriate factory methods
     * for the specific enum type, such as {@code language()}, {@code projectScope()}, or
     * {@code pathScope()}.
     *
     * @return a non-null collection of enum instances to register
     */
    @Nonnull

    /**
     * Controller for managing crawling intervals and delays.
     */
    @Resource
    protected IntervalController intervalController;

    /**
     * Factory for creating crawler clients.
     */
    @Resource
    protected CrawlerClientFactory clientFactory;

    /**
     * Context object containing crawler state and configuration.
     */

import java.util.Collection;
import java.util.Map;

import org.codelibs.core.beans.BeanDesc;
import org.codelibs.core.beans.FieldDesc;
import org.codelibs.core.beans.ParameterizedClassDesc;
import org.codelibs.core.beans.factory.ParameterizedClassDescFactory;
import org.codelibs.core.exception.FieldNotStaticRuntimeException;
import org.codelibs.core.lang.FieldUtil;

/**
 * Implementation class of {@link FieldDesc}.
 *
 * @author koichik