cn.taketoday.core.LinkedMultiValueMap Maven / Gradle / Ivy
/*
* Original Author -> Harry Yang ([email protected]) https://taketoday.cn
* Copyright © TODAY & 2017 - 2022 All Rights Reserved.
*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see [http://www.gnu.org/licenses/]
*/
package cn.taketoday.core;
import java.io.Serial;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import cn.taketoday.util.CollectionUtils;
/**
* Simple implementation of {@link MultiValueMap} that wraps a {@link java.util.LinkedHashMap},
* storing multiple values in an {@link java.util.ArrayList}.
*
* This Map implementation is generally not thread-safe. It is primarily designed
* for data structures exposed from request objects, for use in a single thread only.
*
* @param the key type
* @param the value element type
* @author Arjen Poutsma
* @author Juergen Hoeller
* @author Harry Yang
* @since 4.0 2022/3/17 16:33
*/
public class LinkedMultiValueMap extends DefaultMultiValueMap {
@Serial
private static final long serialVersionUID = 1L;
/**
* Create a new LinkedMultiValueMap that wraps a {@link LinkedHashMap}.
*/
public LinkedMultiValueMap() {
super(new LinkedHashMap<>());
}
/**
* Create a new LinkedMultiValueMap that wraps a {@link LinkedHashMap}
* with an initial capacity that can accommodate the specified number of
* elements without any immediate resize/rehash operations to be expected.
*
* @param expectedSize the expected number of elements (with a corresponding
* capacity to be derived so that no resize/rehash operations are needed)
* @see CollectionUtils#newLinkedHashMap(int)
*/
public LinkedMultiValueMap(int expectedSize) {
super(CollectionUtils.newLinkedHashMap(expectedSize));
}
/**
* Copy constructor: Create a new LinkedMultiValueMap with the same mappings as
* the specified Map. Note that this will be a shallow copy; its value-holding
* List entries will get reused and therefore cannot get modified independently.
*
* @param otherMap the Map whose mappings are to be placed in this Map
* @see #clone()
* @see #deepCopy()
*/
public LinkedMultiValueMap(Map> otherMap) {
super(new LinkedHashMap<>(otherMap));
}
/**
* Create a deep copy of this Map.
*
* @return a copy of this Map, including a copy of each value-holding List entry
* (consistently using an independent modifiable {@link ArrayList} for each entry)
* along the lines of {@code MultiValueMap.addAll} semantics
* @see #addAll(Map)
* @see #clone()
*/
public LinkedMultiValueMap deepCopy() {
LinkedMultiValueMap copy = new LinkedMultiValueMap<>(size());
forEach((key, values) -> copy.put(key, new ArrayList<>(values)));
return copy;
}
/**
* Create a regular copy of this Map.
*
* @return a shallow copy of this Map, reusing this Map's value-holding List entries
* (even if some entries are shared or unmodifiable) along the lines of standard
* {@code Map.put} semantics
* @see #put(Object, List)
* @see #putAll(Map)
* @see LinkedMultiValueMap#LinkedMultiValueMap(Map)
* @see #deepCopy()
*/
@Override
public LinkedMultiValueMap clone() {
return new LinkedMultiValueMap<>(this);
}
}