net.guerlab.cloud.commons.util.TreeUtils Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of guerlab-cloud-commons Show documentation
There is a newer version: 2024.11.0
Show newest version
/*
 * Copyright 2018-2024 guerlab.net and other contributors.
 *
 * Licensed under the GNU LESSER GENERAL PUBLIC LICENSE, Version 3 (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.gnu.org/licenses/lgpl-3.0.html
 *
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package net.guerlab.cloud.commons.util;

import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Map;

import net.guerlab.cloud.commons.Constants;
import net.guerlab.cloud.commons.entity.IOrderlyEntity;
import net.guerlab.cloud.commons.entity.TreeEntity;
import net.guerlab.cloud.commons.entity.TreeNode;
import net.guerlab.commons.collection.CollectionUtil;

/**
 * 树结构工具类.
 *
 * @author guer
 */
@SuppressWarnings("unused")
public final class TreeUtils {

	private TreeUtils() {

	}

	/**
	 * 树型格式化.
	 *
	 * @param data 数据列表
	 * @param   树节点类型
	 * @return 树结构列表
	 */
	public static > List> tree(Collection data) {
		return tree(data, Constants.DEFAULT_PARENT_ID);
	}

	/**
	 * 树型格式化.
	 *
	 * @param data   数据列表
	 * @param rootId 根ID
	 * @param     树节点类型
	 * @param     主键类型
	 * @return 树结构列表
	 */
	public static , K> List> tree(Collection data, K rootId) {
		if (CollectionUtil.isEmpty(data)) {
			return Collections.emptyList();
		}

		List> treeEntities = data.stream().sorted((o1, o2) -> {
			if (o1 instanceof IOrderlyEntity && o2 instanceof IOrderlyEntity) {
				return IOrderlyEntity.compareTo((IOrderlyEntity) o1, (IOrderlyEntity) o2);
			}
			else {
				return 0;
			}
		}).map(TreeUtils::buildTreeEntity).toList();

		Map> map = CollectionUtil.toMap(treeEntities, TreeEntity::getId);
		Map>> childrenMap = CollectionUtil.group(treeEntities, TreeEntity::getParentId);

		List> roots = childrenMap.get(rootId);

		if (CollectionUtil.isEmpty(roots)) {
			return Collections.emptyList();
		}

		childrenMap.forEach((parentId, list) -> {
			TreeEntity parent = map.get(parentId);

			if (parent != null) {
				parent.setChildren(list);
			}
		});

		return roots;
	}

	/**
	 * 构造树形结构对象.
	 *
	 * @param entity 树节点
	 * @param     树节点类型
	 * @param     主键类型
	 * @return 树形结构对象
	 */
	private static , K> TreeEntity buildTreeEntity(E entity) {
		TreeEntity treeEntity = new TreeEntity<>();
		treeEntity.setId(entity.nodeId());
		treeEntity.setParentId(entity.parentId());
		treeEntity.setLabel(entity.label());
		treeEntity.setObject(entity);

		return treeEntity;
	}
}