Bot to give (or take away) roles based on clicking certain reactions.

RoleReactionBot.java

/*
 * Copyright 2018 John Grosh (jagrosh).
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.HashMap;
import net.dv8tion.jda.core.AccountType;
import net.dv8tion.jda.core.JDABuilder;
import net.dv8tion.jda.core.entities.MessageReaction.ReactionEmote;
import net.dv8tion.jda.core.entities.Role;
import net.dv8tion.jda.core.events.message.guild.react.GuildMessageReactionAddEvent;
import net.dv8tion.jda.core.events.message.guild.react.GuildMessageReactionRemoveEvent;
import net.dv8tion.jda.core.hooks.ListenerAdapter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 *
 * @author John Grosh (john.a.grosh@gmail.com)
 */
public class RoleReactionBot extends ListenerAdapter
{
    private final static String FILENAME = "role-reactions.txt";
    private final static Logger LOG = LoggerFactory.getLogger(RoleReactionBot.class);
    private final HashMap<String,Long> map;
    
    public RoleReactionBot() throws Exception
    {
        map = new HashMap<>();
        Files.readAllLines(Paths.get(FILENAME), StandardCharsets.UTF_8).forEach(line ->
        {
            String[] split = line.replace("\uFEFF", "").split(" ", 3);
            try
            {
                long messageId = Long.parseLong(split[0].trim());
                long roleId = Long.parseLong(split[2]);
                map.put(key(messageId, split[1]), roleId);
            }
            catch(Exception e)
            {
                LOG.warn("Could not parse: "+line);
            }
        });
    }

    @Override
    public void onGuildMessageReactionAdd(GuildMessageReactionAddEvent event)
    {
        Role role = event.getGuild().getRoleById(map.getOrDefault(key(event.getMessageIdLong(),event.getReactionEmote()), 0L));
        if(role!=null)
            event.getGuild().getController().addSingleRoleToMember(event.getMember(), role).queue();
    }

    @Override
    public void onGuildMessageReactionRemove(GuildMessageReactionRemoveEvent event)
    {
        Role role = event.getGuild().getRoleById(map.getOrDefault(key(event.getMessageIdLong(),event.getReactionEmote()), 0L));
        if(role!=null)
            event.getGuild().getController().removeSingleRoleFromMember(event.getMember(), role).queue();
    }
    
    
    private static String key(long messageId, ReactionEmote emote)
    {
        return key(messageId, emote.getEmote()==null ? emote.getName(): emote.getEmote().getId());
    }
    
    private static String key(long messageId, String emoji)
    {
        return messageId+"-"+emoji;
    }
    
    public static void main(String[] args) throws Exception
    {
        new JDABuilder(AccountType.BOT)
                .setToken(Files.readAllLines(Paths.get("config.txt")).get(0))
                .addEventListener(new RoleReactionBot())
                .buildAsync();
    }
}