import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * An interface for all filtered multimap types.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
interface FilteredMultimap<K extends @Nullable Object, V extends @Nullable Object>
    extends Multimap<K, V> {
  Multimap<K, V> unfiltered();

  Predicate<? super Entry<K, V>> entryPredicate();

import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * An interface for all filtered multimap types.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
interface FilteredMultimap<K extends @Nullable Object, V extends @Nullable Object>
    extends Multimap<K, V> {
  Multimap<K, V> unfiltered();

  Predicate<? super Entry<K, V>> entryPredicate();

/**
 * Implementation for {@link FilteredMultimap#values()}.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
final class FilteredMultimapValues<K extends @Nullable Object, V extends @Nullable Object>
    extends AbstractCollection<V> {
  @Weak private final FilteredMultimap<K, V> multimap;

  FilteredMultimapValues(FilteredMultimap<K, V> multimap) {

 *
 * @author Louis Wasserman
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
class FilteredKeyMultimap<K extends @Nullable Object, V extends @Nullable Object>
    extends AbstractMultimap<K, V> implements FilteredMultimap<K, V> {
  final Multimap<K, V> unfiltered;
  final Predicate<? super K> keyPredicate;

  FilteredKeyMultimap(Multimap<K, V> unfiltered, Predicate<? super K> keyPredicate) {
    this.unfiltered = checkNotNull(unfiltered);

 * @author Louis Wasserman
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
class FilteredEntryMultimap<K extends @Nullable Object, V extends @Nullable Object>
    extends AbstractMultimap<K, V> implements FilteredMultimap<K, V> {
  final Multimap<K, V> unfiltered;
  final Predicate<? super Entry<K, V>> predicate;

  FilteredEntryMultimap(Multimap<K, V> unfiltered, Predicate<? super Entry<K, V>> predicate) {

 * @author Louis Wasserman
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
class FilteredEntryMultimap<K extends @Nullable Object, V extends @Nullable Object>
    extends AbstractMultimap<K, V> implements FilteredMultimap<K, V> {
  final Multimap<K, V> unfiltered;
  final Predicate<? super Entry<K, V>> predicate;

  FilteredEntryMultimap(Multimap<K, V> unfiltered, Predicate<? super Entry<K, V>> predicate) {

      return new FilteredKeyMultimap<>(
          prev.unfiltered, Predicates.<K>and(prev.keyPredicate, keyPredicate));
    } else if (unfiltered instanceof FilteredMultimap) {
      FilteredMultimap<K, V> prev = (FilteredMultimap<K, V>) unfiltered;
      return filterFiltered(prev, Maps.<K>keyPredicateOnEntries(keyPredicate));
    } else {
      return new FilteredKeyMultimap<>(unfiltered, keyPredicate);
    }