/*
 * Copyright (C) 2007 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect;

import com.google.common.annotations.GwtCompatible;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.Collection;
import java.util.Collections;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import org.checkerframework.checker.nullness.qual.Nullable;

Basic implementation of the SetMultimap interface. It's a wrapper around AbstractMapBasedMultimap that converts the returned collections into Sets. The createCollection method must return a Set. 
Author:
Jared Levy/**
 * Basic implementation of the {@link SetMultimap} interface. It's a wrapper around {@link
 * AbstractMapBasedMultimap} that converts the returned collections into {@code Sets}. The {@link
 * #createCollection} method must return a {@code Set}.
 *
 * @author Jared Levy
 */
@GwtCompatible
abstract class AbstractSetMultimap<K, V> extends AbstractMapBasedMultimap<K, V>
    implements SetMultimap<K, V> {
  
Creates a new multimap that uses the provided map.
Params:
map – place to store the mapping from each key to its corresponding values/**
   * Creates a new multimap that uses the provided map.
   *
   * @param map place to store the mapping from each key to its corresponding values
   */
  protected AbstractSetMultimap(Map<K, Collection<V>> map) {
    super(map);
  }

  @Override
  abstract Set<V> createCollection();

  @Override
  Set<V> createUnmodifiableEmptyCollection() {
    return Collections.emptySet();
  }

  @Override
  <E> Collection<E> unmodifiableCollectionSubclass(Collection<E> collection) {
    return Collections.unmodifiableSet((Set<E>) collection);
  }

  @Override
  Collection<V> wrapCollection(K key, Collection<V> collection) {
    return new WrappedSet(key, (Set<V>) collection);
  }

  // Following Javadoc copied from SetMultimap.

  
{@inheritDoc}
Because a SetMultimap has unique values for a given key, this method returns a Set, instead of the Collection specified in the Multimap interface. /**
   * {@inheritDoc}
   *
   * <p>Because a {@code SetMultimap} has unique values for a given key, this method returns a
   * {@link Set}, instead of the {@link Collection} specified in the {@link Multimap} interface.
   */
  @Override
  public Set<V> get(@Nullable K key) {
    return (Set<V>) super.get(key);
  }

  
{@inheritDoc}
Because a SetMultimap has unique values for a given key, this method returns a Set, instead of the Collection specified in the Multimap interface. /**
   * {@inheritDoc}
   *
   * <p>Because a {@code SetMultimap} has unique values for a given key, this method returns a
   * {@link Set}, instead of the {@link Collection} specified in the {@link Multimap} interface.
   */
  @Override
  public Set<Entry<K, V>> entries() {
    return (Set<Entry<K, V>>) super.entries();
  }

  
{@inheritDoc}
Because a SetMultimap has unique values for a given key, this method returns a Set, instead of the Collection specified in the Multimap interface. /**
   * {@inheritDoc}
   *
   * <p>Because a {@code SetMultimap} has unique values for a given key, this method returns a
   * {@link Set}, instead of the {@link Collection} specified in the {@link Multimap} interface.
   */
  @CanIgnoreReturnValue
  @Override
  public Set<V> removeAll(@Nullable Object key) {
    return (Set<V>) super.removeAll(key);
  }

  
{@inheritDoc}
Because a SetMultimap has unique values for a given key, this method returns a Set, instead of the Collection specified in the Multimap interface. 
Any duplicates in values will be stored in the multimap once. /**
   * {@inheritDoc}
   *
   * <p>Because a {@code SetMultimap} has unique values for a given key, this method returns a
   * {@link Set}, instead of the {@link Collection} specified in the {@link Multimap} interface.
   *
   * <p>Any duplicates in {@code values} will be stored in the multimap once.
   */
  @CanIgnoreReturnValue
  @Override
  public Set<V> replaceValues(@Nullable K key, Iterable<? extends V> values) {
    return (Set<V>) super.replaceValues(key, values);
  }

  
{@inheritDoc}
Though the method signature doesn't say so explicitly, the returned map has Set values. /**
   * {@inheritDoc}
   *
   * <p>Though the method signature doesn't say so explicitly, the returned map has {@link Set}
   * values.
   */
  @Override
  public Map<K, Collection<V>> asMap() {
    return super.asMap();
  }

  
Stores a key-value pair in the multimap.
Params:
key – key to store in the multimap
value – value to store in the multimap
Returns:
true if the method increased the size of the multimap, or false if the multimap already contained the key-value pair/**
   * Stores a key-value pair in the multimap.
   *
   * @param key key to store in the multimap
   * @param value value to store in the multimap
   * @return {@code true} if the method increased the size of the multimap, or {@code false} if the
   *     multimap already contained the key-value pair
   */
  @CanIgnoreReturnValue
  @Override
  public boolean put(@Nullable K key, @Nullable V value) {
    return super.put(key, value);
  }

  
Compares the specified object to this multimap for equality.
Two SetMultimap instances are equal if, for each key, they contain the same values. Equality does not depend on the ordering of keys or values. /**
   * Compares the specified object to this multimap for equality.
   *
   * <p>Two {@code SetMultimap} instances are equal if, for each key, they contain the same values.
   * Equality does not depend on the ordering of keys or values.
   */
  @Override
  public boolean equals(@Nullable Object object) {
    return super.equals(object);
  }

  private static final long serialVersionUID = 7431625294878419160L;
}