Filter.java

package hotsun;

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

import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.Material;
import org.bukkit.event.Listener;
import org.bukkit.inventory.ItemStack;
import org.bukkit.inventory.RecipeChoice;
import org.bukkit.inventory.ShapedRecipe;
import org.bukkit.inventory.meta.ItemMeta;

public class Filter implements Listener 
{
	public static final String durabilityTitle = ChatColor.YELLOW + "Sun Protection:" + ChatColor.WHITE;
	public static final short maxDurability = 100;
	
	ItemStack filter;
	ItemMeta filterMeta;
	
	public Filter()
	{
		this.filter = new ItemStack(Material.LANTERN);
		this.filterMeta = this.filter.getItemMeta();
		
		this.filterMeta.setDisplayName(ChatColor.GOLD + "Filter");
		List<String> lore = new ArrayList<String>();
		lore.add(ChatColor.GOLD + "Used to prevent damage from the sun");
		this.filterMeta.setLore(lore);
		
		this.filter.setItemMeta(filterMeta);
		
		ShapedRecipe filterRecipe = new ShapedRecipe(HotSun.namespace, filter);
		
		RecipeChoice wools = new RecipeChoice.MaterialChoice(Material.WHITE_WOOL, 
				Material.BLACK_WOOL, Material.GRAY_WOOL, Material.BROWN_WOOL);
		
		filterRecipe.shape("WWW", "###", "S~S");
		filterRecipe.setIngredient('#', Material.PAPER);
		filterRecipe.setIngredient('W', wools);
		filterRecipe.setIngredient('~', Material.SUGAR_CANE);
		filterRecipe.setIngredient('S', Material.COAL_BLOCK);
		
		Bukkit.addRecipe(filterRecipe);
	}
	
	public static boolean isFilter(ItemStack filter)
	{
		try
		{
			return filter.getItemMeta().getDisplayName().contains("Filter");
		}
		catch(Exception e)
		{
			return false;
		}
	}
	
	public static short getDurability(ItemStack helmet) 
	{
		if(!helmet.getType().toString().contains("_HELMET"))
			throw new IllegalArgumentException("Only a helmet can have " + durabilityTitle);
		if(!helmet.getItemMeta().hasLore())
			return 0;
		for(String lore : helmet.getItemMeta().getLore())
		{
			if(lore.contains(durabilityTitle))
			{
				String[] lores = lore.split(" ");
				return Short.parseShort(lores[2]);
			}
		}
		return 0;
	}
	
	public static boolean setDurability(ItemStack helmet, short durability)
	{
		if(durability > maxDurability)
			throw new IllegalArgumentException("Durability exceeds maximum");
		if(durability < 0)
			throw new IllegalArgumentException("Durability must be a positive amount");
		if(!helmet.getType().toString().contains("_HELMET"))
			throw new IllegalArgumentException("Filter can only be applied to a helmet");
		
		if(helmet.getItemMeta().hasLore())
		{
			List<String> lores = helmet.getItemMeta().getLore();
			int index = -1;
			for(String lore : lores)
			{
				if(lore.contains(Filter.durabilityTitle))
				{
					index=lores.indexOf(lore);
				}
			}
			if(index!=-1)
			{
				lores.set(index, durabilityTitle + " " + durability + " / " + maxDurability); 
			}
			else
			{
				lores.add(durabilityTitle + " " + durability + " / " + maxDurability);
			}
			helmet.getItemMeta().setLore(lores);
			return true;
		}
		else
		{
			List<String> lores = new ArrayList<String>();
			lores.add(durabilityTitle + " " + durability + " / " + maxDurability);
			Bukkit.broadcastMessage(lores.get(0));
			helmet.getItemMeta().setLore(lores);
			return true;
		}
	}
}

HotSun.java

package hotsun;

import org.bukkit.NamespacedKey;
import org.bukkit.plugin.Plugin;
import org.bukkit.plugin.java.JavaPlugin;

public class HotSun extends JavaPlugin
{
	Plugin instance;
	static NamespacedKey namespace;
	
	@Override
	public void onEnable()
	{
		instance = this;
		namespace = new NamespacedKey(this, this.getDescription().getName());		
		
		Timers.timer(this);
		getServer().getPluginManager().registerEvents(new InventoryClicker(), this);
		
		@SuppressWarnings("unused")
		Filter filter = new Filter();
	}
	
	@Override
	public void onDisable()
	{
		
	}
}

InventoryClicker.java

package hotsun;

import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.inventory.InventoryClickEvent;
import org.bukkit.event.player.AsyncPlayerChatEvent;

public class InventoryClicker implements Listener
{
	@EventHandler
	public void said(AsyncPlayerChatEvent event)
	{
		if(event.getMessage().equals("test"))
		{
			Player player = event.getPlayer();
			if(player.getInventory().getHelmet() != null)
			{
				if(player.getInventory().getHelmet().getItemMeta().hasLore())
				{
					for(String lore: player.getInventory().getHelmet().getItemMeta().getLore())
					{
						player.sendMessage(lore);
					}
				}
				else
				{
					player.sendMessage("No Lore");
				}
			}
		}
	}
	
	@EventHandler
	public void click(InventoryClickEvent event)
	{
		if(event.getCursor() != null)
		{
			if(Filter.isFilter(event.getCursor()))
			{
				if(event.getCurrentItem().getType().toString().contains("_HELMET"))
				{
					if(Filter.setDurability(event.getCurrentItem(), Filter.maxDurability))
					{
						Player player = (Player) event.getWhoClicked();
						player.setItemOnCursor(null);
						player.updateInventory();
						player.sendMessage("You applied a filter to your helmet! (Click again if it disappeared)");
					}
				}
			}
		}
	}
}

Timers.java

package hotsun;

import org.bukkit.Bukkit;
import org.bukkit.Location;
import org.bukkit.World;
import org.bukkit.block.Block;
import org.bukkit.entity.Player;
import org.bukkit.inventory.ItemStack;
import org.bukkit.plugin.Plugin;

public class Timers 
{
	public static final short SUN_DAMAGE = 3; 
	
	public static boolean isDay(Player player)
	{
		// Adjusted 8 "minutes" for sunlight
		// 0 = 06:00
		return (player.getWorld().getTime() < 13884 || player.getWorld().getTime() > 22634);
	}
	
	public static void timer(Plugin plugin)
	{
		for(Player player : plugin.getServer().getOnlinePlayers())
		{
			if(!player.isDead()) 
			{
				Location location = player.getLocation();
				location.setY(location.getY()+1);
				Block block = location.getBlock();
				if(block.getLightFromSky() > 10 && block.getLightLevel() > 9 && isDay(player) && player.getWorld().getEnvironment() == World.Environment.NORMAL)
				{
					try
					{
						ItemStack helmet = player.getInventory().getHelmet();
						if(Filter.getDurability(helmet) > SUN_DAMAGE)
						{
							Filter.setDurability(helmet, (short) (Filter.getDurability(helmet) - SUN_DAMAGE));
						}
						else
						{
							Filter.setDurability(helmet, (short) 0);
							player.damage(SUN_DAMAGE);
							player.setFireTicks(60);
						}
					}
					catch(Exception e)
					{
						e.printStackTrace();
					}					
					player.damage(SUN_DAMAGE);
					player.setFireTicks(60);
				}
			}
		}
		
		Bukkit.getServer().getScheduler().scheduleSyncDelayedTask(plugin, new Runnable() {
			 
			  public void run() {
			      timer(plugin);
			  }
			}, 20L);// 60 L == 3 sec, 20 ticks == 1 sec
	}
}