Wagon getWagon(String protocol) throws UnsupportedProtocolException;

    @Deprecated
    Wagon getWagon(Repository repository) throws UnsupportedProtocolException, WagonConfigurationException;

    //
    // Retriever
    //
    void getArtifact(Artifact artifact, ArtifactRepository repository, TransferListener transferListener, boolean force)
            throws TransferFailedException, ResourceDoesNotExistException;

import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * This class provides a skeletal implementation of the {@link ListIterator} interface across a
 * fixed number of elements that may be retrieved by position. It does not support {@link #remove},
 * {@link #set}, or {@link #add}.
 *
 * @author Jared Levy
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault

import com.google.common.util.concurrent.ListenableFutureTask;
import java.io.Serializable;
import java.util.Map;
import java.util.concurrent.Executor;

/**
 * Computes or retrieves values, based on a key, for use in populating a {@link LoadingCache}.
 *
 * <p>Most implementations will only need to implement {@link #load}. Other methods may be
 * overridden as desired.
 *
 * <p>Usage example:
 *

 */
@Deprecated
public interface ArtifactMetadataSource extends org.apache.maven.repository.legacy.metadata.ArtifactMetadataSource {

    ResolutionGroup retrieve(MetadataResolutionRequest request) throws ArtifactMetadataRetrievalException;

    ResolutionGroup retrieve(
            Artifact artifact, ArtifactRepository localRepository, List<ArtifactRepository> remoteRepositories)
            throws ArtifactMetadataRetrievalException;

     *
     * @param key the key for which to retrieve the session data, must not be {@code null}
     * @return the session data associated with the key or {@code null} if none
     */
    @Nullable
    <T> T get(@Nonnull Key<T> key);

    /**
     * Retrieve of compute the data associated with the specified key.
     *
     * @param key the key for which to retrieve the session data, must not be {@code null}

 */
package org.apache.maven.rtinfo;

/**
 * Provides information about the current Maven runtime.
 *
 * @since 3.0.2
 */
public interface RuntimeInformation {

    /**
     * Retrieves the current Maven version, for example "3.0.2".
     *
     * @return The current Maven version or an empty string if unknown, never {@code null}.
     */
    String getMavenVersion();

    /**

    /**
     * Obtain the {@link Type} from the specified {@code id}.
     * If no type is known for {@code id}, the registry will
     * create a custom {@code Type} for it.
     *
     * @param id the id of the type to retrieve
     * @return the type
     */
    @Nonnull
    @Override
    default Type require(@Nonnull String id) {

    }
  }

  public void testBroken() {
    Iterator<Object> broken = new BrokenAbstractSequentialIterator();
    assertTrue(broken.hasNext());
    // We can't retrieve even the known first element:
    try {
      broken.next();
      fail();
    } catch (MyException expected) {
    }
    try {
      broken.next();
      fail();
    } catch (MyException expected) {

 * with any other implementation of this interface.
 *
 * <p>If you have your own graph implementation based around a custom node type {@code MyNode},
 * which has a method {@code getParents()} that retrieves its predecessors in a graph:
 *
 * <pre>{@code
 * someGraphAlgorithm(startNode, MyNode::getParents);
 * }</pre>
 *
 * <p>If you have some other mechanism for returning the predecessors of a node, or one that doesn't

 * any other implementation of this interface.
 *
 * <p>If you have your own graph implementation based around a custom node type {@code MyNode},
 * which has a method {@code getChildren()} that retrieves its successors in a graph:
 *
 * <pre>{@code
 * someGraphAlgorithm(startNode, MyNode::getChildren);
 * }</pre>
 *
 * <p>If you have some other mechanism for returning the successors of a node, or one that doesn't