Java tutorial
/* * This file is part of LuckPerms, licensed under the MIT License. * * Copyright (c) lucko (Luck) <luck@lucko.me> * Copyright (c) contributors * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in all * copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. */ package me.lucko.luckperms.common.treeview; import com.google.common.collect.Maps; import java.util.Map; import java.util.Optional; import java.util.concurrent.ConcurrentHashMap; /** * Represents one "branch" or "level" of the node tree */ public class TreeNode { private Map<String, TreeNode> children = null; // lazy init public synchronized Map<String, TreeNode> getChildMap() { if (children == null) { children = new ConcurrentHashMap<>(); } return children; } public Optional<Map<String, TreeNode>> getChildren() { return Optional.ofNullable(children); } public int getDeepSize() { if (children == null) { return 1; } else { return children.values().stream().mapToInt(TreeNode::getDeepSize).sum(); } } public ImmutableTreeNode makeImmutableCopy() { if (children == null) { return new ImmutableTreeNode(null); } else { return new ImmutableTreeNode(children.entrySet().stream() .map(e -> Maps.immutableEntry(e.getKey(), e.getValue().makeImmutableCopy()))); } } }