*/
  public static boolean elementsEqual(Iterable<?> iterable1, Iterable<?> iterable2) {
    if (iterable1 instanceof Collection && iterable2 instanceof Collection) {
      Collection<?> collection1 = (Collection<?>) iterable1;
      Collection<?> collection2 = (Collection<?>) iterable2;
      if (collection1.size() != collection2.size()) {
        return false;
      }
    }

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

import javax.inject.Named;
import javax.inject.Singleton;

import java.util.Collection;

import org.apache.maven.api.Event;
import org.apache.maven.api.EventType;
import org.apache.maven.api.Listener;
import org.apache.maven.eventspy.EventSpy;
import org.apache.maven.execution.ExecutionEvent;

/**

    assertPermutationsCount(1, Collections2.permutations(Collections.<Integer>emptyList()));
    assertPermutationsCount(1, Collections2.permutations(newArrayList(1)));
    assertPermutationsCount(2, Collections2.permutations(newArrayList(1, 2)));
    assertPermutationsCount(6, Collections2.permutations(newArrayList(1, 2, 3)));
    assertPermutationsCount(5040, Collections2.permutations(newArrayList(1, 2, 3, 4, 5, 6, 7)));

        }
    }

    /**
     * chains a collection of {@link WorkspaceReader}s
     * @param workspaceReaderCollection the collection of readers, might be empty but never <code>null</code>
     * @return if the collection contains only one item returns the single item, otherwise creates a new
     *         {@link MavenChainedWorkspaceReader} chaining all readers in the order of the given collection.
     */

  /**
   * For documenting collections that support no optional features, such as {@link
   * java.util.Collections#emptySet}
   */
  NONE;

  private final Set<Feature<? super Collection>> implied;

  CollectionFeature(Feature<? super Collection>... implied) {
    this.implied = copyToSet(implied);
  }

  @Override
  public Set<Feature<? super Collection>> getImpliedFeatures() {
    return implied;

    private final Collection<String> scopesToCollectForCurrentProject;

    private final Collection<String> scopesToResolveForCurrentProject;

    private final Collection<String> scopesToCollectForAggregatedProjects;

    private final Collection<String> scopesToResolveForAggregatedProjects;

    private volatile Collection<?> lastDependencyArtifacts = Collections.emptyList();

    }

    @Override
    public boolean addAll(Collection<? extends V> collection) {
      addAll(0, collection);
      return true;
    }

    @CanIgnoreReturnValue
    @Override
    public boolean addAll(int index, Collection<? extends V> elements) {
      checkNotNull(elements);
      checkPositionIndex(index, 0);

    @Nonnull
    Optional<Artifact> getRootArtifact();

    @Nonnull
    Optional<DependencyCoordinates> getRoot();

    @Nonnull
    Collection<DependencyCoordinates> getDependencies();

    @Nonnull
    Collection<DependencyCoordinates> getManagedDependencies();

    boolean getVerbose();

    @Nonnull
    PathScope getPathScope();

    /**

    return Collections.unmodifiableCollection(collection);
  }

  @Override
  public void clear() {
    // Clear each collection, to make previously returned collections empty.
    for (Collection<V> collection : map.values()) {
      collection.clear();
    }
    map.clear();
    totalSize = 0;
  }

  // Views

  /**
   * {@inheritDoc}
   *

 * 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 java.util.Collection;

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

/**