朱俊杰
2022-02-10 37a84e66917d6e22e03e31b0a115e2c16d23ed21
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package com.genersoft.iot.vmp.utils.node;
 
import com.genersoft.iot.vmp.utils.CollectionUtil;
 
import java.util.List;
 
/**
 * 森林节点归并类
 *
 */
public class ForestNodeMerger {
 
    /**
     * 将节点数组归并为一个森林(多棵树)(填充节点的children域)
     * 时间复杂度为O(n^2)
     *
     * @param items 节点域
     * @return 多棵树的根节点集合
     */
    public static <T extends INode<T>> List<T> merge(List<T> items) {
        ForestNodeManager<T> forestNodeManager = new ForestNodeManager<>(items);
        items.forEach(forestNode -> {
            if (forestNode.getParentId() != null) {
                INode<T> node = forestNodeManager.getTreeNodeAt(forestNode.getParentId());
                if (node != null) {
                    node.getChildren().add(forestNode);
                } else {
                    forestNodeManager.addParentId(forestNode.getId());
                }
            }
        });
        return forestNodeManager.getRoot();
    }
 
    public static <T extends INode<T>> List<T> merge(List<T> items, String[] parentIds) {
        ForestNodeManager<T> forestNodeManager = new ForestNodeManager<>(items);
        items.forEach(forestNode -> {
            if (forestNode.getParentId() != null) {
                INode<T> node = forestNodeManager.getTreeNodeAt(forestNode.getParentId());
                if (CollectionUtil.contains(parentIds, forestNode.getId())){
                    forestNodeManager.addParentId(forestNode.getId());
                } else {
                    if (node != null){
                        node.getChildren().add(forestNode);
                    }
                }
            }
        });
        return forestNodeManager.getRoot();
    }
}