import org.apache.maven.api.annotations.Experimental;
import org.apache.maven.api.annotations.Nonnull;

/**
 * A listener for session events.
 * TODO: open this to other events like similar to {@code org.apache.maven.eventspy.EventSpy}
 *
 * @since 4.0.0
 */
@Experimental
@FunctionalInterface
@Consumer
public interface Listener {
    void onEvent(@Nonnull Event event);

    private CWD(Path directory) {
        this.directory = directory;
    }

    @Nonnull
    @Override
    public Path get() {
        return directory;
    }

    /**
     * Resolves against current cwd, resulting path is normalized.
     *
     * @throws NullPointerException if {@code seg} is {@code null}.
     */
    @Nonnull
    public Path resolve(String seg) {
        requireNonNull(seg, "seg");

     * @return {@code true} if this range contains the specified version, {@code false} otherwise
     */
    boolean contains(@Nonnull Version version);

    /**
     * {@return the string representation of this version}
     */
    @Nonnull
    @Override
    String toString();

import java.util.function.Function;
import java.util.function.UnaryOperator;

import org.apache.maven.api.Service;
import org.apache.maven.api.annotations.Experimental;
import org.apache.maven.api.annotations.Nonnull;
import org.apache.maven.api.annotations.Nullable;

/**
 * The Interpolator service provides methods for variable substitution in strings and maps.

 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.model.root;

import java.nio.file.Path;

import org.apache.maven.api.annotations.Nonnull;
import org.apache.maven.api.annotations.Nullable;

/**
 * Interface used to locate the root directory for a given project.
 *
 * The root locator is usually looked up from the plexus container.

     *
     * @return file paths to place on the different tool options
     */
    @Nonnull
    Map<PathType, List<Path>> getDispatchedPaths();

    /**
     * {@return all dependencies associated with their paths}
     * Some dependencies may be associated with a null value if there is no path available.
     */
    @Nonnull
    Map<Dependency, Path> getDependencies();

    /**

    /**
     * Reads an XML node from an input stream.
     */
    @Nonnull
    public static XmlNode read(InputStream input, @Nullable InputLocationBuilder locationBuilder)
            throws XMLStreamException {
        return getService().doRead(input, locationBuilder);
    }

    /**
     * Reads an XML node from a reader.
     */
    @Nonnull
    public static XmlNode read(Reader reader) throws XMLStreamException {

   * getInstance(TypeToken.of(Foo.class))}.
   */
  <T extends @NonNull B> @Nullable T getInstance(Class<T> type);

  /**
   * Returns the value the specified type is mapped to, or {@code null} if no entry for this type is
   * present. This will only return a value that was bound to this specific type, not a value that
   * may have been bound to a subtype.
   */
  <T extends @NonNull B> @Nullable T getInstance(TypeToken<T> type);

  /**

   * getInstance(TypeToken.of(Foo.class))}.
   */
  <T extends @NonNull B> @Nullable T getInstance(Class<T> type);

  /**
   * Returns the value the specified type is mapped to, or {@code null} if no entry for this type is
   * present. This will only return a value that was bound to this specific type, not a value that
   * may have been bound to a subtype.
   */
  <T extends @NonNull B> @Nullable T getInstance(TypeToken<T> type);

  /**

import org.apache.maven.api.annotations.Nonnull;

import static java.util.Objects.requireNonNull;

/**
 * Base class for requests.
 *
 * @since 4.0.0
 */
@Experimental
abstract class BaseRequest<S extends ProtoSession> implements Request<S> {

    private final S session;
    private final RequestTrace trace;

    protected BaseRequest(@Nonnull S session) {
        this(session, null);
    }