@SuppressWarnings("serial") // we're overriding default serialization
@ElementTypesAreNonnullByDefault
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 = Iterables.getOnlyElement(map.entrySet());

 * to avoid code-size bloat.
 *
 * @author Hayward Chan
 */
@ElementTypesAreNonnullByDefault
final class ImmutableEnumMap<K, V> extends ForwardingImmutableMap<K, V> {
  static <K, V> ImmutableMap<K, V> asImmutable(Map<K, V> map) {
    for (Entry<K, V> entry : checkNotNull(map).entrySet()) {
      checkNotNull(entry.getKey());
      checkNotNull(entry.getValue());
    }
    return new ImmutableEnumMap<K, V>(map);
  }

@SuppressWarnings("serial") // we're overriding default serialization
@ElementTypesAreNonnullByDefault
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 = Iterables.getOnlyElement(map.entrySet());