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);

     */
    @Nonnull
    Optional<List<String>> goals();

    /**
     * Returns the target POM model version for upgrades.
     * Supported values include "4.0.0" and "4.1.0".
     *
     * @return an {@link Optional} containing the model version, or empty if not specified
     */
    @Nonnull
    Optional<String> modelVersion();

    /**

 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.api;

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

/**
 * Represents a repository backed by an IDE workspace, the output of a build session,
 * or similar ad-hoc collections of artifacts. This repository is considered read-only

     * @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.

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

public interface Lookup extends Service {
    /**
     * Performs a lookup for given typed component.
     *
     * @param type The component type.
     * @return The component.
     * @param <T> The component type.
     * @throws LookupException if no such component or there is some provisioning related issue.
     */
    @Nonnull
    <T> T lookup(Class<T> type);

    /**

    /**
     * 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 {

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

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

/**
 * Interface that defines some kind of enums that can be extended by Maven plugins or extensions.
 *
 * Implementation must have {@code equals()} and {@code hashCode()} implemented, so implementations of this interface

      Class<? super @NonNull E> type, E[] emptyArrayForContents, Iterable<? extends E> contents) {
    List<E> setContents = new ArrayList<>();
    for (E e : contents) {
      if (!setContents.contains(e)) {
        setContents.add(e);
      }
    }
    return new MinimalSet<>(type, setContents.toArray(emptyArrayForContents));
  }

  private MinimalSet(Class<? super @NonNull E> type, E... contents) {

      Class<? super @NonNull E> type, E[] emptyArrayForContents, Iterable<? extends E> contents) {
    List<E> setContents = new ArrayList<>();
    for (E e : contents) {
      if (!setContents.contains(e)) {
        setContents.add(e);
      }
    }
    return new MinimalSet<>(type, setContents.toArray(emptyArrayForContents));
  }

  private MinimalSet(Class<? super @NonNull E> type, E... contents) {