com.wl4g.component.common.collection.multimap.MultiValueMap Maven / Gradle / Ivy
/*
* Copyright 2017 ~ 2025 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
*
* 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.wl4g.component.common.collection.multimap;
import java.util.List;
import java.util.Map;
/**
* Extension of the {@code Map} interface that stores multiple values.
*
* @param
* the key type
* @param
* the value element type
*/
public interface MultiValueMap extends Map> {
/**
* 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
*/
V getFirst(K key);
/**
* 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, V value);
/**
* 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 values);
/**
* 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 values);
/**
* {@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, V value) {
if (!containsKey(key)) {
add(key, value);
}
}
/**
* Set the given single value under the given key.
*
* @param key
* the key
* @param value
* the value to set
*/
void set(K key, V value);
/**
* Set the given values under.
*
* @param values
* the values.
*/
void setAll(Map values);
/**
* Return a {@code Map} with the first values contained in this
* {@code MultiValueMap}.
*
* @return a single value representation of this map
*/
Map toSingleValueMap();
}