com.power4j.coca.kit.common.collection.tree.TreeUtil Maven / Gradle / Ivy
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/*
* Copyright 2021 ChenJun ([email protected] & https://github.com/John-Chan)
*
* Licensed under the GNU LESSER GENERAL PUBLIC LICENSE 3.0;
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.gnu.org/licenses/lgpl.html
*
* 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.power4j.coca.kit.common.collection.tree;
import lombok.Builder;
import lombok.Getter;
import lombok.experimental.UtilityClass;
import org.apache.commons.lang3.ObjectUtils;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.Set;
import java.util.function.BiConsumer;
import java.util.function.Consumer;
import java.util.function.Function;
import java.util.stream.Collectors;
/**
* @author CJ ([email protected])
* @date 2022/1/19
* @since 1.0
*/
@UtilityClass
public class TreeUtil {
/**
* 在给定的集合中查找根节点
* @param source 数据源
* @param idGetter ID取值方法
* @param pidGetter PID取值方法
* @param ID 类型
* @param 对象
* @return 返回根节点MAP
*/
public Map findAncestors(Map source, Function idGetter,
Function pidGetter) {
Map output = new HashMap<>(8);
Set skipSet = new HashSet<>(8);
for (T node : source.values()) {
if (skipSet.contains(idGetter.apply(node))) {
continue;
}
T ancestor = findAncestor(source, node, skipSet, idGetter, pidGetter);
output.put(idGetter.apply(ancestor), ancestor);
}
return output;
}
T findAncestor(Map source, T child, Set skipSet, Function idGetter,
Function pidGetter) {
T parent = source.get(pidGetter.apply(child));
if (Objects.nonNull(parent)) {
skipSet.add(idGetter.apply(child));
return findAncestor(source, parent, skipSet, idGetter, pidGetter);
}
return child;
}
/**
* 填充子级
* @param source 数据源
* @param roots 根节点
* @param nodeOp 各种操作函数
* @param ID 类型
* @param 节点类型
*/
public void fetch(Collection source, Collection roots, NodeOp nodeOp) {
Map sourceMap = source.stream()
.collect(Collectors.toMap(nodeOp.idGetter, Function.identity(), (x, y) -> y, LinkedHashMap::new));
Map rootMap = roots.stream()
.collect(Collectors.toMap(nodeOp.idGetter, Function.identity(), (x, y) -> y, LinkedHashMap::new));
fetch(sourceMap, rootMap, nodeOp);
}
/**
* 填充子级
* @param source 数据源
* @param roots 根节点
* @param nodeOp 各种操作函数
* @param ID 类型
* @param 节点类型
*/
public void fetch(Map source, Map roots, NodeOp nodeOp) {
if (roots.isEmpty()) {
return;
}
for (T node : source.values()) {
if (null == node) {
continue;
}
final ID id = Objects.requireNonNull(nodeOp.idGetter.apply(node));
if (roots.containsKey(id)) {
continue;
}
final ID parentId = nodeOp.pidGetter.apply(node);
final T parentNode = Optional.ofNullable(roots.get(parentId)).orElseGet(() -> source.get(parentId));
if (null != parentNode) {
nodeOp.childConsumer.accept(parentNode, node);
}
}
}
/**
* 迭代树节点
* @param roots 根节点
* @param accessOp 各种操作函数
* @param consumer 节点消费函数
* @param ID 类型
* @param 节点类型
*/
public void treeWalk(Collection roots, AccessOp accessOp,
Consumer consumer) {
for (final T node : roots) {
consumer.accept(node);
Collection children = accessOp.childrenGetter.apply(node);
if (ObjectUtils.isNotEmpty(children)) {
treeWalk(children, accessOp, consumer);
}
}
}
/**
* 树节点转list
* @param roots 根节点
* @param accessOp 各种操作函数
* @param ID 类型
* @param 节点类型
* @return 返回节点MAP
*/
public List flatten(Collection roots, AccessOp accessOp) {
List list = new ArrayList<>(roots.size());
treeWalk(roots, accessOp, list::add);
return list;
}
@Getter
@Builder
public static class NodeOp {
/**
* 取ID的方法
*/
private final Function idGetter;
/**
* 取PID的方法
*/
private final Function pidGetter;
/**
* 添加子元素的方法
*/
private final BiConsumer childConsumer;
}
@Getter
@Builder
public static class AccessOp {
/**
* 取ID的方法
*/
private final Function idGetter;
/**
* 取PID的方法
*/
private final Function pidGetter;
/**
* 访问子元素列表的方法
*/
private final Function> childrenGetter;
}
}