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.storage.dao.file; import com.google.common.base.Splitter; import com.google.common.collect.Maps; import me.lucko.luckperms.common.utils.DateUtil; import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.File; import java.io.IOException; import java.nio.charset.StandardCharsets; import java.nio.file.Files; import java.util.Iterator; import java.util.Map; import java.util.UUID; import java.util.concurrent.ConcurrentHashMap; public class FileUuidCache { private static final Splitter KV_SPLIT = Splitter.on('=').omitEmptyStrings(); private static final Splitter TIME_SPLIT = Splitter.on('|').omitEmptyStrings(); // the map for lookups private final Map<String, Map.Entry<UUID, Long>> lookupMap = new ConcurrentHashMap<>(); /** * Adds a mapping to the cache * * @param uuid the uuid of the player * @param username the username of the player */ public void addMapping(UUID uuid, String username) { lookupMap.put(username.toLowerCase(), Maps.immutableEntry(uuid, DateUtil.unixSecondsNow())); } /** * Gets the most recent uuid which connected with the given username, or null * * @param username the username to lookup with * @return a uuid, or null */ public UUID lookupUUID(String username) { Map.Entry<UUID, Long> ret = lookupMap.get(username.toLowerCase()); return ret == null ? null : ret.getKey(); } /** * Gets the most recent username used by a given uuid * * @param uuid the uuid to lookup with * @return a username, or null */ public String lookupUsername(UUID uuid) { String username = null; Long time = Long.MIN_VALUE; for (Map.Entry<String, Map.Entry<UUID, Long>> ent : lookupMap.entrySet()) { if (!ent.getValue().getKey().equals(uuid)) { continue; } Long t = ent.getValue().getValue(); if (t > time) { time = t; username = ent.getKey(); } } return username; } public void load(File file) { if (!file.exists()) { return; } try (BufferedReader reader = Files.newBufferedReader(file.toPath(), StandardCharsets.UTF_8)) { String entry; while ((entry = reader.readLine()) != null) { entry = entry.trim(); if (entry.isEmpty() || entry.startsWith("#")) { continue; } Iterator<String> parts = KV_SPLIT.split(entry).iterator(); if (!parts.hasNext()) continue; String key = parts.next(); if (!parts.hasNext()) continue; String value = parts.next(); UUID uid; Long t; // contains a time (backwards compat) if (value.contains("|")) { // try to split and extract the time element from the end. Iterator<String> valueParts = TIME_SPLIT.split(value).iterator(); if (!valueParts.hasNext()) continue; String uuid = valueParts.next(); if (!valueParts.hasNext()) continue; String time = valueParts.next(); try { uid = UUID.fromString(uuid); } catch (IllegalArgumentException e) { continue; } try { t = Long.parseLong(time); } catch (NumberFormatException e) { continue; } } else { // just parse from the value try { uid = UUID.fromString(value); } catch (IllegalArgumentException e) { continue; } t = 0L; } lookupMap.put(key, Maps.immutableEntry(uid, t)); } } catch (IOException e) { e.printStackTrace(); } } public void save(File file) { try (BufferedWriter writer = Files.newBufferedWriter(file.toPath(), StandardCharsets.UTF_8)) { writer.write("# LuckPerms UUID lookup cache"); writer.newLine(); for (Map.Entry<String, Map.Entry<UUID, Long>> ent : lookupMap.entrySet()) { String out = ent.getKey() + "=" + ent.getValue().getKey().toString() + "|" + ent.getValue().getValue().toString(); writer.write(out); writer.newLine(); } writer.flush(); } catch (IOException e) { e.printStackTrace(); } } }