* "https://github.com/google/guava/wiki/CollectionUtilitiesExplained#maps">{@code Maps}</a>.
 *
 * @author Kevin Bourrillion
 * @author Mike Bostock
 * @author Isaac Shum
 * @author Louis Wasserman
 * @since 2.0
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public final class Maps {
  private Maps() {}

  private enum EntryFunction implements Function<Entry<?, ?>, @Nullable Object> {

     * @return 指定されたキーと値を持つ{@link HashMap}を構築するための{@literal Maps}
     */
    public static <KEY, VALUE> Maps<KEY, VALUE> hashMap(final KEY key, final VALUE value) {
        return new Maps<>(new HashMap<KEY, VALUE>()).$(key, value);
    }

    /**
     * 指定されたキーと値を持つ{@link Hashtable}を構築するための{@literal Maps}を返します。
     *
     * @param <KEY>
     *            <code>Map</code>のキーの型
     * @param <VALUE>

    assertTrue(entries.contains(Maps.immutableEntry("a", true)));
    assertTrue(entries.contains(Maps.<String, @Nullable Boolean>immutableEntry("b", null)));
    assertTrue(
        entries.contains(Maps.<@Nullable String, @Nullable Boolean>immutableEntry(null, null)));

    assertFalse(entries.contains(Maps.<String, @Nullable Boolean>immutableEntry("c", null)));

    Map<C, V> row = Maps.safeGet(rowMap(), rowKey);
    return row != null && Maps.safeContainsKey(row, columnKey);
  }

  @Override
  @CheckForNull
  public V get(@CheckForNull Object rowKey, @CheckForNull Object columnKey) {
    Map<C, V> row = Maps.safeGet(rowMap(), rowKey);
    return (row == null) ? null : Maps.safeGet(row, columnKey);
  }

  @Override

    assertTrue(entries.contains(Maps.immutableEntry("a", true)));
    assertTrue(entries.contains(Maps.<String, @Nullable Boolean>immutableEntry("b", null)));
    assertTrue(
        entries.contains(Maps.<@Nullable String, @Nullable Boolean>immutableEntry(null, null)));

    assertFalse(entries.contains(Maps.<String, @Nullable Boolean>immutableEntry("c", null)));

    assertFalse(entries.remove((Object) 4.5));
    assertFalse(entries.contains(Maps.immutableEntry("foo", Collections.singletonList(1))));
    assertFalse(entries.remove(Maps.immutableEntry("foo", Collections.singletonList(1))));
    assertFalse(entries.contains(Maps.immutableEntry("foo", Sets.newLinkedHashSet(asList(1, 2)))));
    assertFalse(entries.remove(Maps.immutableEntry("foo", Sets.newLinkedHashSet(asList(1, 2)))));

    assertEquals(Maps.immutableEntry("foo", 5), entryIterator.next());
    assertEquals(Maps.immutableEntry("bar", 4), entryIterator.next());
    assertEquals(Maps.immutableEntry("foo", 3), entryIterator.next());
    assertEquals(Maps.immutableEntry("cow", 2), entryIterator.next());
    assertEquals(Maps.immutableEntry("bar", 1), entryIterator.next());

    }

    @Override
    Set<K> createKeySet() {
      @WeakOuter
      class KeySetImpl extends Maps.KeySet<K, Collection<V>> {
        KeySetImpl() {
          super(AsMap.this);
        }

        @Override
        public boolean removeAll(Collection<?> c) {
          return removeEntriesIf(Maps.<K>keyPredicateOnEntries(in(c)));
        }

        @Override

    assertTrue(entries.contains(Maps.immutableEntry("a", true)));
    assertTrue(entries.contains(Maps.<String, @Nullable Boolean>immutableEntry("b", null)));
    assertTrue(
        entries.contains(Maps.<@Nullable String, @Nullable Boolean>immutableEntry(null, null)));

    assertFalse(entries.contains(Maps.<String, @Nullable Boolean>immutableEntry("c", null)));

    @Override
    protected Map<AnEnum, String> create(Entry<AnEnum, String>[] entries) {
      Map<AnEnum, String> map = Maps.newHashMap();
      for (Entry<AnEnum, String> entry : entries) {
        map.put(entry.getKey(), entry.getValue());
      }
      return Maps.immutableEnumMap(map);
    }
  }

  @J2ktIncompatible
  @GwtIncompatible // suite
  public static Test suite() {