*
 * <p>The time complexity of all collection-returning accessors is O(1), since views are returned.
 *
 * @author James Sexton
 * @author Joshua O'Madadhain
 * @author Omar Darwish
 * @param <N> Node parameter type
 * @param <E> Edge parameter type
 */
class StandardNetwork<N, E> extends AbstractNetwork<N, E> {
  private final boolean isDirected;
  private final boolean allowsParallelEdges;

 *
 * <p>The time complexity of all collection-returning accessors is O(1), since views are returned.
 *
 * @author James Sexton
 * @author Joshua O'Madadhain
 * @author Omar Darwish
 * @param <N> Node parameter type
 * @param <V> Value parameter type
 */
class StandardValueGraph<N, V> extends AbstractValueGraph<N, V> {
  private final boolean isDirected;

 *
 * <p>A pipeline of {@code ClosingFuture}s is a tree of steps. Each step represents either an
 * asynchronously-computed intermediate value, or else an exception that indicates the failure or
 * cancellation of the operation so far. The only way to extract the value or exception from a step
 * is by declaring that step to be the last step of the pipeline. Nevertheless, we refer to the
 * "value" of a successful step or the "result" (value or exception) of any step.