/*
 * Copyright 2002-2019 the original author or 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
 *
 *      https://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 org.springframework.util;

import java.util.List;
import java.util.Map;

import org.springframework.lang.Nullable;

Extension of the Map interface that stores multiple values.
Author:Arjen Poutsma
Type parameters:
  • <K> – the key type
  • <V> – the value element type
Since:3.0
/** * Extension of the {@code Map} interface that stores multiple values. * * @author Arjen Poutsma * @since 3.0 * @param <K> the key type * @param <V> the value element type */
public interface MultiValueMap<K, V> extends Map<K, List<V>> {
Return the first value for the given key.
Params:
  • key – the key
Returns:the first value for the specified key, or null if none
/** * Return the first value for the given key. * @param key the key * @return the first value for the specified key, or {@code null} if none */
@Nullable V getFirst(K key);
Add the given single value to the current list of values for the given key.
Params:
  • key – the key
  • value – the value to be added
/** * Add the given single value to the current list of values for the given key. * @param key the key * @param value the value to be added */
void add(K key, @Nullable V value);
Add all the values of the given list to the current list of values for the given key.
Params:
  • key – they key
  • values – the values to be added
Since:5.0
/** * Add all the values of the given list to the current list of values for the given key. * @param key they key * @param values the values to be added * @since 5.0 */
void addAll(K key, List<? extends V> values);
Add all the values of the given MultiValueMap to the current values.
Params:
  • values – the values to be added
Since:5.0
/** * Add all the values of the given {@code MultiValueMap} to the current values. * @param values the values to be added * @since 5.0 */
void addAll(MultiValueMap<K, V> values);
Add the given value, only when the map does not contain the given key.
Params:
  • key – the key
  • value – the value to be added
Since:5.2
/** * {@link #add(Object, Object) Add} the given value, only when the map does not * {@link #containsKey(Object) contain} the given key. * @param key the key * @param value the value to be added * @since 5.2 */
default void addIfAbsent(K key, @Nullable V value) { if (!containsKey(key)) { add(key, value); } }
Set the given single value under the given key.
Params:
  • key – the key
  • value – the value to set
/** * Set the given single value under the given key. * @param key the key * @param value the value to set */
void set(K key, @Nullable V value);
Set the given values under.
Params:
  • values – the values.
/** * Set the given values under. * @param values the values. */
void setAll(Map<K, V> values);
Return a Map with the first values contained in this MultiValueMap.
Returns:a single value representation of this map
/** * Return a {@code Map} with the first values contained in this {@code MultiValueMap}. * @return a single value representation of this map */
Map<K, V> toSingleValueMap(); }