com.wl4g.infra.common.collection.multimap.LinkedMultiValueMap Maven / Gradle / Ivy
/*
* Copyright 2017 ~ 2025 the original author or authors. James Wong
*
* 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.infra.common.collection.multimap;
import java.io.Serializable;
import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import javax.annotation.Nullable;
/**
* Simple implementation of {@link MultiValueMap} that wraps a
* {@link LinkedHashMap}, storing multiple values in a {@link LinkedList}.
*
*
* 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
*/
public class LinkedMultiValueMap implements MultiValueMap, Serializable, Cloneable {
private static final long serialVersionUID = 3801124242820219131L;
private final Map> targetMap;
/**
* Create a new LinkedMultiValueMap that wraps a {@link LinkedHashMap}.
*/
public LinkedMultiValueMap() {
this.targetMap = new LinkedHashMap<>();
}
/**
* Create a new LinkedMultiValueMap that wraps a {@link LinkedHashMap} with
* the given initial capacity.
*
* @param initialCapacity
* the initial capacity
*/
public LinkedMultiValueMap(int initialCapacity) {
this.targetMap = new LinkedHashMap<>(initialCapacity);
}
/**
* 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) {
this.targetMap = new LinkedHashMap<>(otherMap);
}
// MultiValueMap implementation
@Override
@Nullable
public V getFirst(K key) {
List values = this.targetMap.get(key);
return (values != null && !values.isEmpty() ? values.get(0) : null);
}
@Override
public void add(K key, @Nullable V value) {
List values = this.targetMap.computeIfAbsent(key, k -> new LinkedList<>());
values.add(value);
}
@Override
public void addAll(K key, List values) {
List currentValues = this.targetMap.computeIfAbsent(key, k -> new LinkedList<>());
currentValues.addAll(values);
}
@Override
public void addAll(MultiValueMap values) {
for (Entry> entry : values.entrySet()) {
addAll(entry.getKey(), entry.getValue());
}
}
@Override
public void set(K key, @Nullable V value) {
List values = new LinkedList<>();
values.add(value);
this.targetMap.put(key, values);
}
@Override
public void setAll(Map values) {
values.forEach(this::set);
}
@Override
public Map toSingleValueMap() {
LinkedHashMap singleValueMap = new LinkedHashMap<>(this.targetMap.size());
this.targetMap.forEach((key, values) -> {
if (values != null && !values.isEmpty()) {
singleValueMap.put(key, values.get(0));
}
});
return singleValueMap;
}
// Map implementation
@Override
public int size() {
return this.targetMap.size();
}
@Override
public boolean isEmpty() {
return this.targetMap.isEmpty();
}
@Override
public boolean containsKey(Object key) {
return this.targetMap.containsKey(key);
}
@Override
public boolean containsValue(Object value) {
return this.targetMap.containsValue(value);
}
@Override
@Nullable
public List get(Object key) {
return this.targetMap.get(key);
}
@Override
@Nullable
public List put(K key, List value) {
return this.targetMap.put(key, value);
}
@Override
@Nullable
public List remove(Object key) {
return this.targetMap.remove(key);
}
@Override
public void putAll(Map> map) {
this.targetMap.putAll(map);
}
@Override
public void clear() {
this.targetMap.clear();
}
@Override
public Set keySet() {
return this.targetMap.keySet();
}
@Override
public Collection> values() {
return this.targetMap.values();
}
@Override
public Set>> entrySet() {
return this.targetMap.entrySet();
}
/**
* 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 LinkedList} for each entry) along the lines of
* {@code MultiValueMap.addAll} semantics
* @since 4.2
* @see #addAll(MultiValueMap)
* @see #clone()
*/
public LinkedMultiValueMap deepCopy() {
LinkedMultiValueMap copy = new LinkedMultiValueMap<>(this.targetMap.size());
this.targetMap.forEach((key, value) -> copy.put(key, new LinkedList<>(value)));
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
* @since 4.2
* @see #put(Object, List)
* @see #putAll(Map)
* @see LinkedMultiValueMap#LinkedMultiValueMap(Map)
* @see #deepCopy()
*/
@Override
public LinkedMultiValueMap clone() {
return new LinkedMultiValueMap<>(this);
}
@Override
public boolean equals(@Nullable Object obj) {
return this.targetMap.equals(obj);
}
@Override
public int hashCode() {
return this.targetMap.hashCode();
}
@Override
public String toString() {
return this.targetMap.toString();
}
}