}
    }

    static class ExtensionInterpolator extends MavenTransformer {
        ExtensionInterpolator(UnaryOperator<String> transformer) {
            super(transformer);
        }

        public XmlNode transform(XmlNode node) {
            return super.transform(node);
        }
    }

                accessResult.setAccessResultData(null);
                try {
                    final Transformer transformer = ComponentUtil.getComponent(accessResultData.getTransformerName());
                    if (transformer == null) {
                        // no transformer
                        logger.warn("Transformer not found: name={}, url={}", accessResultData.getTransformerName(), accessResult.getUrl());

import org.eclipse.aether.deployment.DeployRequest;
import org.eclipse.aether.installation.InstallRequest;

import static java.util.Objects.requireNonNull;

/**
 * Inliner POM transformer. The goal of this transformer is to fix Maven 3 issue about emitting (installing, deploying)
 * unusable POMs when using CI Friendly Versions.
 *
 * @since TBD
 */
@Singleton
@Named

import org.eclipse.aether.deployment.DeployRequest;
import org.eclipse.aether.installation.InstallRequest;
import org.eclipse.aether.spi.artifact.transformer.ArtifactTransformer;

import static java.util.Objects.requireNonNull;

/**
 * Maven specific transformer.
 */
@Singleton
@Named
final class MavenTransformer implements ArtifactTransformer {
    private final TransformerManager transformerManager;

        output.cancel(false);
        throw new SomeUncheckedException();
      }
    }
    Transformer transformer = new Transformer();
    SettableFuture<Object> input = SettableFuture.create();

    ListenableFuture<Object> output = transform(input, transformer, directExecutor());
    transformer.output = output;

    input.set("foo");
    assertTrue(output.isCancelled());
  }

        output.cancel(false);
        throw new SomeUncheckedException();
      }
    }
    Transformer transformer = new Transformer();
    SettableFuture<Object> input = SettableFuture.create();

    ListenableFuture<Object> output = transform(input, transformer, directExecutor());
    transformer.output = output;

    input.set("foo");
    assertTrue(output.isCancelled());
  }

import org.apache.maven.api.model.Model;

/**
 * A model transformer.
 *
 * @since 4.0.0
 */
@Experimental
public interface ModelTransformer {

    /**
     * Apply a transformation on the file model.
     *
     * @param model the input model
     * @param problems the problem collector to report any issues encountered during transformation
     * @return the transformed model, or the input model if no transformation is needed

import org.apache.maven.project.MavenProject;
import org.eclipse.aether.RepositorySystemSession;
import org.eclipse.aether.deployment.DeployRequest;
import org.eclipse.aether.installation.InstallRequest;

/**
 * Maven transformer manager.
 *
 * @since 4.0.0
 */
public interface TransformerManager {
    InstallRequest remapInstallArtifacts(RepositorySystemSession session, InstallRequest request);

Existing Groovy methods will not be removed immediately.

## Consequences

* If we would have used `Closure`, we must instead use `Action<T>`, `Spec<T>`, `Callable<T>`, or `Transformer<OUT, IN>`.
* We need to ensure all APIs that are exposed in the Groovy DSL go through runtime decoration.
Runtime decoration mixes in methods that use Groovy Closures to maintain consistent behavior in Groovy DSL.

    public void transform(MavenProject project, RepositorySystemSession session, ModelSource src, Path tgt)
            throws ModelBuilderException, XMLStreamException, IOException {
        throw new IllegalStateException("This transformer does not use this call.");
    }

    protected static final String NAMESPACE_FORMAT = "http://maven.apache.org/POM/%s";