WorldStarDriver.java

package net.andrewcpu.worldstar;

import org.apache.commons.io.FileUtils;
import org.bukkit.*;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.entity.EntityDamageEvent;
import org.bukkit.event.entity.PlayerDeathEvent;
import org.bukkit.plugin.java.JavaPlugin;
import org.bukkit.potion.PotionEffect;

import java.io.File;
import java.io.IOException;

public class WorldStarDriver extends JavaPlugin implements Listener {
    /*
     * THIS IS INCOMPLETE!
     * YOU WILL NEED TO ADD A MECHANISM FOR REMEMBERING IF A PLAYER WHO IS JOINING HAS PLAYED ON THE CURRENT HARDCORE WORLD
     * (YOU NEED TO MAKE SURE YOU CLEAR THEIR INVENTORY IF THEY WEREN'T ONLINE WHEN THE SERVER RESET.)
     * YOU ALSO NEED TO MAKE SURE TO TELEPORT THEM INTO THE HARDCORE WORLD IF THEY WERE IN "WORLD" WHEN THEY DISCONNECTED.
     * 
     * THE CODE BELOW IS PROVIDED AS IS, AND IS ONLY MEANT TO BE AN EXAMPLE OF UNLOADING A WORLD, DELETING IT, 
     * AND REGENERATING IT WHILE THE SERVER IS RUNNING
     * 
     * -Andrewcpu
     */
    public void onEnable() {
        getServer().getPluginManager().registerEvents(this, this);
        if(getWorld("hardcore") == null){
            createWorld("hardcore");
        }
    }
    
    @EventHandler
    public void onDeath(PlayerDeathEvent event){
        death();
    }

    @EventHandler
    public void onDamage(EntityDamageEvent event){
        if(event.getEntity() instanceof Player){
            if(((Player) event.getEntity()).getHealth() - event.getFinalDamage() <= 0){
                event.setCancelled(true);
                death();
            }
        }
    }

    private void reset(){
        World world = getWorld("hardcore");
        getServer().unloadWorld(world, false);
        deleteDirectory(world.getWorldFolder());
        createWorld("hardcore");
    }

    public void death(){
        moveToVoid();
        Bukkit.getScheduler().scheduleSyncDelayedTask(this, () -> {
            reset();
            exitTheVoid();
        }, 100);
    }
    
    public void moveToVoid(){
        for(Player p : Bukkit.getOnlinePlayers()){
            p.setGameMode(GameMode.SPECTATOR);
            p.teleport(getWorld("world").getSpawnLocation());
            p.sendTitle("Creating a new world...", "This will only be a moment", 20 * 2, 20 * 5, 20 * 2);
        }
    }

    public void exitTheVoid(){
        for(Player player : Bukkit.getOnlinePlayers()){
            player.getInventory().clear();
            player.getEquipment().clear();
            player.setHealth(20);
            player.setSaturation(5);
            player.setFoodLevel(20);
            for (PotionEffect effect : player.getActivePotionEffects()) {
                player.removePotionEffect(effect.getType());
            }
            player.setGameMode(GameMode.SURVIVAL);
            player.teleport(getWorld("hardcore").getSpawnLocation());
        }
    }

    boolean deleteDirectory(File directoryToBeDeleted) {
        try {
            FileUtils.deleteDirectory(directoryToBeDeleted);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return directoryToBeDeleted.delete();
    }

    private World getWorld(String worldName) {
        return Bukkit.getWorlds().stream().filter(w -> w.getName().equals(worldName)).findFirst().orElse(null);
    }

    private World createWorld(String worldName) {
        WorldCreator wc = new WorldCreator(worldName);
        wc.environment(World.Environment.NORMAL);
        wc.type(WorldType.NORMAL);
        wc.hardcore(true);
        return wc.createWorld();
    }
}