/**
   * A sensible implementation of {@link Multiset#elementSet} in terms of the following methods:
   * {@link ForwardingMultiset#clear}, {@link ForwardingMultiset#contains}, {@link
   * ForwardingMultiset#containsAll}, {@link ForwardingMultiset#count}, {@link
   * ForwardingMultiset#isEmpty}, the {@link Set#size} and {@link Set#iterator} methods of {@link
   * ForwardingMultiset#entrySet}, and {@link ForwardingMultiset#remove(Object, int)}. In many

  }

  /**
   * A sensible implementation of {@link SortedMultiset#elementSet} in terms of the following
   * methods: {@link SortedMultiset#clear}, {@link SortedMultiset#comparator}, {@link
   * SortedMultiset#contains}, {@link SortedMultiset#containsAll}, {@link SortedMultiset#count},
   * {@link SortedMultiset#firstEntry} {@link SortedMultiset#headMultiset}, {@link

   * you override {@link #listIterator()}, you may wish to override {@link #iterator} to forward to
   * this implementation.
   *
   * @since 7.0
   */
  protected Iterator<E> standardIterator() {
    return listIterator();
  }

  /**
   * A sensible default implementation of {@link #listIterator()}, in terms of {@link

  }

  /**
   * A sensible implementation of {@link Map#values} in terms of the following methods: {@link
   * ForwardingMap#clear}, {@link ForwardingMap#containsValue}, {@link ForwardingMap#isEmpty},
   * {@link ForwardingMap#size}, and the {@link Set#iterator} method of {@link
   * ForwardingMap#entrySet}. In many cases, you may wish to override {@link ForwardingMap#values}

  public E lower(@ParametricNullness E e) {
    return delegate().lower(e);
  }

  /**
   * A sensible definition of {@link #lower} in terms of the {@code descendingIterator} method of
   * {@link #headSet(Object, boolean)}. If you override {@link #headSet(Object, boolean)}, you may
   * wish to override {@link #lower} to forward to this implementation.
   */
  @CheckForNull
  protected E standardLower(@ParametricNullness E e) {

   * #add}, you may wish to override {@link #addAll} to forward to this implementation.
   *
   * @since 7.0
   */
  protected boolean standardAddAll(Collection<? extends E> collection) {
    return Iterators.addAll(this, collection.iterator());
  }

  /**
   * A sensible definition of {@link #remove} in terms of {@link #iterator}, using the iterator's

   * #add}, you may wish to override {@link #addAll} to forward to this implementation.
   *
   * @since 7.0
   */
  protected boolean standardAddAll(Collection<? extends E> collection) {
    return Iterators.addAll(this, collection.iterator());
  }

  /**
   * A sensible definition of {@link #remove} in terms of {@link #iterator}, using the iterator's

            <link>http://jakarta.apache.org/commons/logging/apidocs/</link>
            <link>http://jakarta.apache.org/commons/pool/apidocs/</link>
            <link>http://www.junit.org/junit/javadoc/</link>
            <link>http://logging.apache.org/log4j/docs/api/</link>
            <link>http://jakarta.apache.org/regexp/apidocs/</link>
            <link>http://jakarta.apache.org/velocity/api/</link>
          </links>
        </configuration>

   */
  public abstract N target();

  /**
   * If this {@link EndpointPair} {@link #isOrdered()} returns the {@link #source()}; otherwise,
   * returns an arbitrary (but consistent) endpoint of the origin edge.
   */
  public final N nodeU() {
    return nodeU;
  }

  /**
   * Returns the node {@link #adjacentNode(Object) adjacent} to {@link #nodeU()} along the origin

     * <p>When {@link #isIncremental()} is {@code false}, then all elements of the parameter are returned as {@link ChangeType#ADDED}.</p>
     *
     * <p>
     *     This method allows querying properties of type {@link org.gradle.api.file.RegularFileProperty} and {@link org.gradle.api.file.DirectoryProperty} for changes.