TestTransformer transformer3 = new TestTransformer("transformer3");

        ResponseData responseData = new ResponseData();
        responseData.setUrl("http://example.com");

        ResultData result1 = transformer1.transform(responseData);
        ResultData result2 = transformer2.transform(responseData);
        ResultData result3 = transformer3.transform(responseData);

        TestTransformer transformer1 = new TestTransformer();
        NameTrackingTransformer transformer2 = new NameTrackingTransformer();

        transformer1.setName("transformer1");
        transformer2.setName("transformer2");

        assertEquals("transformer1", transformer1.getName());
        assertEquals("transformer2", transformer2.getName());

 */
package org.codelibs.fess.crawler.transformer;

import org.codelibs.fess.crawler.entity.AccessResultData;
import org.codelibs.fess.crawler.entity.ResponseData;
import org.codelibs.fess.crawler.entity.ResultData;

/**
 * The Transformer interface defines methods for transforming response data
 * and retrieving data from access results.
 */
public interface Transformer {

    /**

 */
package org.codelibs.fess.crawler.transformer.impl;

import org.codelibs.fess.crawler.transformer.Transformer;

/**
 * An abstract base class for transformers.
 * Provides basic implementation for managing the transformer's name.
 *
 */
public abstract class AbstractTransformer implements Transformer {

    /**
     * Creates a new instance of AbstractTransformer.
     */

		</postConstruct>
	</component>

	<component name="fessFileTransformer" class="org.codelibs.fess.crawler.transformer.FessFileTransformer" instance="singleton">
		<property name="name">"fessFileTransformer"</property>
	</component>

	<component name="fessStandardTransformer" class="org.codelibs.fess.crawler.transformer.FessStandardTransformer" instance="singleton">
		<property name="name">"fessStandardTransformer"</property>
	</component>

                accessResult.setAccessResultData(null);
                try {
                    final Transformer transformer = ComponentUtil.getComponent(accessResultData.getTransformerName());
                    if (transformer == null) {
                        // no transformer
                        logger.warn("No transformer: {}", accessResultData.getTransformerName());
                        continue;
                    }

    @Override
    public Object getData(final AccessResultData<?> accessResultData) {
        // check transformer name
        if (!getName().equals(accessResultData.getTransformerName())) {
            throw new CrawlerSystemException(
                    "Transformer is invalid. Use " + accessResultData.getTransformerName() + ". This transformer is " + getName() + ".");
        }
        final byte[] data = accessResultData.getData();

fess-crawler-parent/
├── fess-crawler/              # Core crawler framework
│   ├── client/               # Protocol clients (HTTP, FTP, SMB, etc.)
│   ├── extractor/           # Content extractors
│   ├── transformer/         # Data transformers
│   └── service/             # Core services
├── fess-crawler-lasta/       # LastaFlute DI integration
└── fess-crawler-opensearch/  # OpenSearch backend
```

### Key Components

import org.apache.maven.api.annotations.Nonnull;
import org.apache.maven.api.di.Named;
import org.apache.maven.api.model.Model;

/**
 * Interface for model transformers that can modify Maven project models at different stages of processing.
 * <p>
 * Model transformers allow plugins and extensions to modify the POM model during the build process.
 * Transformations can be applied at three different stages:
 * <ol>

    final Multimap<K, V1> fromMultimap;
    final EntryTransformer<? super K, ? super V1, V2> transformer;

    TransformedEntriesMultimap(
        Multimap<K, V1> fromMultimap, EntryTransformer<? super K, ? super V1, V2> transformer) {
      this.fromMultimap = checkNotNull(fromMultimap);
      this.transformer = checkNotNull(transformer);
    }

    Collection<V2> transform(@ParametricNullness K key, Collection<V1> values) {