}

  static <N, E> UndirectedNetworkConnections<N, E> of() {
    return new UndirectedNetworkConnections<>(HashBiMap.<E, N>create(EXPECTED_DEGREE));
  }

  static <N, E> UndirectedNetworkConnections<N, E> ofImmutable(Map<E, N> incidentEdges) {
    return new UndirectedNetworkConnections<>(ImmutableBiMap.copyOf(incidentEdges));
  }

  @Override
  public Set<N> adjacentNodes() {

//
public interface RepositoryCache {

    /**
     * Puts the specified data into the cache. <strong>Warning:</strong> The cache will directly save the provided
     * reference. If the cached data is mutable, i.e. could be modified after being put into the cache, the caller is
     * responsible for creating a copy of the original data and store the copy in the cache.
     *

            new LinkedHashMap<N, V>(INNER_CAPACITY, INNER_LOAD_FACTOR));
      default:
        throw new AssertionError(incidentEdgeOrder.type());
    }
  }

  static <N, V> UndirectedGraphConnections<N, V> ofImmutable(Map<N, V> adjacentNodeValues) {
    return new UndirectedGraphConnections<>(ImmutableMap.copyOf(adjacentNodeValues));
  }

  @Override
  public Set<N> adjacentNodes() {

    return new UndirectedMultiNetworkConnections<>(
        new HashMap<E, N>(INNER_CAPACITY, INNER_LOAD_FACTOR));
  }

  static <N, E> UndirectedMultiNetworkConnections<N, E> ofImmutable(Map<E, N> incidentEdges) {
    return new UndirectedMultiNetworkConnections<>(ImmutableMap.copyOf(incidentEdges));
  }

  @LazyInit private transient @Nullable Reference<Multiset<N>> adjacentNodesReference;

  @Override

 */
@GwtCompatible
@SuppressWarnings("serial") // we're overriding default serialization
final class ImmutableEnumSet<E extends Enum<E>> extends ImmutableSet<E> {
  static <E extends Enum<E>> ImmutableSet<E> asImmutable(EnumSet<E> set) {
    switch (set.size()) {
      case 0:
        return ImmutableSet.of();
      case 1:
        return ImmutableSet.of(getOnlyElement(set));
      default:

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

import static java.util.Objects.requireNonNull;

/**
 * A thin wrapper for a {@link Path} that serves as "current working directory" value. Hence, this class
 * is mutable (as CWD may be changed), but allows transition only to existing directories.
 */
public final class CWD implements Supplier<Path> {
    /**
     * Creates instance out of {@link Path}.
     */

@GwtCompatible
@SuppressWarnings("serial") // we're overriding default serialization
final class ImmutableEnumMap<K extends Enum<K>, V> extends IteratorBasedImmutableMap<K, V> {
  static <K extends Enum<K>, V> ImmutableMap<K, V> asImmutable(EnumMap<K, V> map) {
    switch (map.size()) {
      case 0:
        return ImmutableMap.of();
      case 1:
        Entry<K, V> entry = getOnlyElement(map.entrySet());

            new LinkedHashMap<N, V>(INNER_CAPACITY, INNER_LOAD_FACTOR));
      default:
        throw new AssertionError(incidentEdgeOrder.type());
    }
  }

  static <N, V> UndirectedGraphConnections<N, V> ofImmutable(Map<N, V> adjacentNodeValues) {
    return new UndirectedGraphConnections<>(ImmutableMap.copyOf(adjacentNodeValues));
  }

  @Override
  public Set<N> adjacentNodes() {

    this.loggerName = ownerOfLogger.getName();
  }

  Logger get() {
    /*
     * We use double-checked locking. We could the try racy single-check idiom, but that would
     * depend on Logger to not contain mutable state.
     *
     * We could use Suppliers.memoizingSupplier here, but I micro-optimized to this implementation
     * to avoid the extra class for the lambda (and maybe more for memoizingSupplier itself) and the

        return this;
      }
    }

    ImmutableSet<E> toImmutableSet() {
      if (set == null) {
        return ImmutableSet.of();
      }
      ImmutableSet<E> ret = ImmutableEnumSet.asImmutable(set);
      set = null; // subsequent manual manipulation of the accumulator mustn't affect ret
      return ret;
    }
  }

  @GwtIncompatible
  @SuppressWarnings({"rawtypes", "unchecked"})