return null;
    }

    /**
     * Adds a thumbnail generator to the manager.
     *
     * @param generator the thumbnail generator to add
     */
    public void add(final ThumbnailGenerator generator) {
        if (generator.isAvailable()) {
            if (logger.isDebugEnabled()) {
                logger.debug("{} is available.", generator.getName());
            }
            generatorList.add(generator);

// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//

import org.codelibs.fess.util.ComponentUtil;
import org.codelibs.fess.util.InputStreamThread;

import jakarta.annotation.PostConstruct;

/**
 * Command-based thumbnail generator that executes external commands to create thumbnails.
 * Uses external tools through command execution to generate thumbnail images from documents.
 */
public class CommandGenerator extends BaseThumbnailGenerator {

  public static <E> QueueTestSuiteBuilder<E> using(TestQueueGenerator<E> generator) {
    return new QueueTestSuiteBuilder<E>().usingGenerator(generator);
  }

  private boolean runCollectionTests = true;

  /**
   * Specify whether to skip the general collection tests. Call this method when testing a

// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//

        emptyInstanceGenerated.put(type.getType(), freshness.get());
        return emptyInstance;
      }
    }
    Method generate = GENERATORS.get(rawType);
    if (generate != null) {
      ImmutableList<Parameter> params = Invokable.from(generate).getParameters();
      List<Object> args = Lists.newArrayListWithCapacity(params.size());
      TypeVariable<?>[] typeVars = rawType.getTypeParameters();

// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//

      generator.addSampleInstances((Class) entry.getKey(), entry.getValue());
    }
    return generator;
  }

  private static @Nullable Object generateDummyArg(Parameter param, FreshValueGenerator generator)
      throws ParameterNotInstantiableException {
    if (isNullable(param)) {
      return null;
    }
    Object arg = generator.generateFresh(param.getType());

                    # Use a memory stream to decouple generator iteration
                    # from the keepalive timer. A producer task pulls items
                    # from the generator independently, so
                    # `anyio.fail_after` never wraps the generator's
                    # `__anext__` directly - avoiding CancelledError that
                    # would finalize the generator and also working for sync

// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//