ToggleFall.java

package com.colt.togglefall;

import java.util.ArrayList;
import java.util.List;

import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.World;
import org.bukkit.command.Command;
import org.bukkit.command.CommandSender;
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.player.PlayerQuitEvent;
import org.bukkit.plugin.java.JavaPlugin;

public class ToggleFall extends JavaPlugin implements Listener {
	
	ArrayList<String> activePlayers;
	List<String> worlds;
	
	@Override
	public void onEnable() {
		Bukkit.getServer().getPluginManager().registerEvents(this, this);
		activePlayers = new ArrayList<String>();
		worlds = getConfig().getStringList("worlds");
		saveDefaultConfig();
	}
	
	@Override
	public void onDisable() {
		activePlayers.clear();
	}
	
	@Override
	public boolean onCommand(CommandSender sender, Command cmd, String label, String[] args) {
		if (cmd.getName().equalsIgnoreCase("togglefall") || (cmd.getName().equalsIgnoreCase("tf"))) { 
			if(sender instanceof Player) {
				Player player = (Player)sender;
				if(player.hasPermission("nofall.use")) {
					if(activePlayers.contains(player.getName())) {
						activePlayers.remove(player.getName());
						player.sendMessage(ChatColor.GOLD + "Fall Damage now enabled" + ChatColor.RED + "(You will take fall damage)");
					} else {
						activePlayers.add(player.getName());
						player.sendMessage(ChatColor.GOLD + "Fall Damage now disabled" + ChatColor.GREEN + "(You will not take fall damage)");
					}
					return true;
				}
			}
		}
		return false;
	}
	
	@EventHandler
	public void playerQuit(PlayerQuitEvent event) {
		if(activePlayers.contains(event.getPlayer().getName())) {
			activePlayers.remove(event.getPlayer().getName());
		}
	}
	
	@EventHandler
	public void onEntityDamage(EntityDamageEvent event) {
		if (event.getEntity() instanceof Player) {
			Player player = (Player)event.getEntity();
			if(activePlayers.contains(player.getName()) && event.getCause() == EntityDamageEvent.DamageCause.FALL && player.hasPermission("nofall.use")) {
			    for(String w : worlds) {
			    	World world = Bukkit.getWorld(w);
					if(player.getWorld() == world) {
						event.setCancelled(true);
						break;
					}
			    }
			}
		}
	}
}