* @since 2.0
 */
@GwtCompatible
public final class HashBiMap<K extends @Nullable Object, V extends @Nullable Object>
    extends IteratorBasedAbstractMap<K, V> implements BiMap<K, V>, Serializable {

  /** Returns a new, empty {@code HashBiMap} with the default initial capacity (16). */
  public static <K extends @Nullable Object, V extends @Nullable Object> HashBiMap<K, V> create() {
    return create(16);
  }

  /**

 * @since 2.0
 */
@GwtCompatible
public final class HashBiMap<K extends @Nullable Object, V extends @Nullable Object>
    extends AbstractMap<K, V> implements BiMap<K, V>, Serializable {

  /** Returns a new, empty {@code HashBiMap} with the default initial capacity (16). */
  public static <K extends @Nullable Object, V extends @Nullable Object> HashBiMap<K, V> create() {
    return create(16);
  }

  /**

            "switzerland", "franc");
    HashBiMap<String, String> bimap = HashBiMap.create(map);
    assertThat(bimap.get("canada")).isEqualTo("dollar");
    assertThat(bimap.inverse().get("dollar")).isEqualTo("canada");
  }

  private static final int N = 1000;

  public void testBashIt() throws Exception {
    BiMap<Integer, Integer> bimap = HashBiMap.create(N);
    BiMap<Integer, Integer> inverse = bimap.inverse();

            "switzerland", "franc");
    HashBiMap<String, String> bimap = HashBiMap.create(map);
    assertThat(bimap.get("canada")).isEqualTo("dollar");
    assertThat(bimap.inverse().get("dollar")).isEqualTo("canada");
  }

  private static final int N = 1000;

  public void testBashIt() throws Exception {
    BiMap<Integer, Integer> bimap = HashBiMap.create(N);
    BiMap<Integer, Integer> inverse = bimap.inverse();

    super(inEdgeMap, outEdgeMap, selfLoopCount);
  }

  static <N, E> DirectedNetworkConnections<N, E> of() {
    return new DirectedNetworkConnections<>(
        HashBiMap.<E, N>create(EXPECTED_DEGREE), HashBiMap.<E, N>create(EXPECTED_DEGREE), 0);
  }

  static <N, E> DirectedNetworkConnections<N, E> ofImmutable(
      Map<E, N> inEdges, Map<E, N> outEdges, int selfLoopCount) {

 */

package com.google.common.graph;

import static com.google.common.graph.GraphConstants.EXPECTED_DEGREE;

import com.google.common.collect.BiMap;
import com.google.common.collect.HashBiMap;
import com.google.common.collect.ImmutableBiMap;
import java.util.Collections;
import java.util.Map;
import java.util.Set;

/**
 * An implementation of {@link NetworkConnections} for undirected networks.
 *

 * bimap containing the same entries as this bimap but with reversed keys and values.
 *
 * <h3>Implementations</h3>
 *
 * <ul>
 *   <li>{@link ImmutableBiMap}
 *   <li>{@link HashBiMap}
 *   <li>{@link EnumBiMap}
 *   <li>{@link EnumHashBiMap}
 * </ul>
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/NewCollectionTypesExplained#bimap">{@code BiMap}</a>.

 * bimap containing the same entries as this bimap but with reversed keys and values.
 *
 * <h3>Implementations</h3>
 *
 * <ul>
 *   <li>{@link ImmutableBiMap}
 *   <li>{@link HashBiMap}
 *   <li>{@link EnumBiMap}
 *   <li>{@link EnumHashBiMap}
 * </ul>
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/NewCollectionTypesExplained#bimap">{@code BiMap}</a>.

  static <K, V> BiMap<K, V> generateBimap(@Nullable K key, @Nullable V value) {
    return generateHashBiMap(key, value);
  }

  @Generates
  static <K, V> HashBiMap<K, V> generateHashBiMap(@Nullable K key, @Nullable V value) {
    HashBiMap<K, V> bimap = HashBiMap.create();
    bimap.put(key, value);
    return bimap;
  }

  @Generates
  static <K, V> ImmutableBiMap<K, V> generateImmutableBimap(K key, V value) {

  static <K, V> BiMap<K, V> generateBimap(@Nullable K key, @Nullable V value) {
    return generateHashBiMap(key, value);
  }

  @Generates
  static <K, V> HashBiMap<K, V> generateHashBiMap(@Nullable K key, @Nullable V value) {
    HashBiMap<K, V> bimap = HashBiMap.create();
    bimap.put(key, value);
    return bimap;
  }

  @Generates
  static <K, V> ImmutableBiMap<K, V> generateImmutableBimap(K key, V value) {