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package io.hmit.common.utils;
import io.hmit.common.validator.AssertUtils;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
/**
* 树形结构工具类，如：菜单、部门等
*
* @author zsh 408538940@qq.com
* @since 1.0.0
*/
public class TreeUtils {
/**
* 根据pid，构建树节点
*/
public static <T extends TreeNode> List<T> build(List<T> treeNodes, Long pid) {
//pid不能为空
AssertUtils.isNull(pid, "pid");
List<T> treeList = new ArrayList<>();
for (T treeNode : treeNodes) {
if (pid.equals(treeNode.getPid())) {
treeList.add(findChildren(treeNodes, treeNode));
}
}
return treeList;
}
/**
* 查找子节点
*/
private static <T extends TreeNode> T findChildren(List<T> treeNodes, T rootNode) {
for (T treeNode : treeNodes) {
if (rootNode.getId().equals(treeNode.getPid())) {
rootNode.getChildren().add(findChildren(treeNodes, treeNode));
}
}
return rootNode;
}
/**
* 构建树节点
*/
public static <T extends TreeNode> List<T> build(List<T> treeNodes) {
List<T> result = new ArrayList<>();
//list转map
Map<Long, T> nodeMap = new LinkedHashMap<>(treeNodes.size());
for (T treeNode : treeNodes) {
nodeMap.put(treeNode.getId(), treeNode);
}
for (T node : nodeMap.values()) {
T parent = nodeMap.get(node.getPid());
if (parent != null && !(node.getId().equals(parent.getId()))) {
parent.getChildren().add(node);
continue;
}
result.add(node);
}
return result;
}
}