ItemSoulBottle.java

package minestrapteam.mods.minestrappolation.item;

import minestrapteam.mods.minestrappolation.Config;
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.item.Item;
import net.minecraft.item.ItemStack;
import net.minecraft.nbt.NBTTagCompound;
import net.minecraft.util.EnumChatFormatting;
import net.minecraft.world.World;
import net.minecraftforge.fml.relauncher.Side;
import net.minecraftforge.fml.relauncher.SideOnly;

import java.util.List;

public class ItemSoulBottle extends Item
{

	public ItemSoulBottle()
	{
		this.setMaxStackSize(1);
	}

	@Override
	public void onCreated(ItemStack stack, World worldIn, EntityPlayer playerIn)
	{
		if (stack.getTagCompound() == null)
		{
			stack.setTagCompound(new NBTTagCompound());
		}
		if (!worldIn.isRemote)
		{
			stack.getTagCompound().setInteger("xp", 0);
		}
	}

	@Override
	public ItemStack onItemRightClick(ItemStack stack, World world, EntityPlayer player)
	{
		if (stack.getTagCompound() == null)
		{
			stack.setTagCompound(new NBTTagCompound());
			if (!world.isRemote)
			{
				stack.getTagCompound().setInteger("xp", 0);
			}
		}
		if (player.isSneaking())
		{
			if (player.experienceLevel > 1)
			{
				int stored = stack.getTagCompound().getInteger("xp");
				if (stored < Config.soulBottleStorage)
				{
					player.addExperienceLevel(-1);
					stack.getTagCompound().setInteger("xp", stored + 1);
				}
			}
		}
		else
		{
			int stored = stack.getTagCompound().getInteger("xp");
			if (stored >= 1)
			{
				player.addExperienceLevel(1);
				stack.getTagCompound().setInteger("xp", stored - 1);
			}
		}
		return stack;
	}

	@Override
	@SideOnly(Side.CLIENT)
	public void addInformation(ItemStack stack, EntityPlayer playerIn, List tooltip, boolean advanced)
	{
		if (stack.getTagCompound() == null)
		{
			stack.setTagCompound(new NBTTagCompound());
		}
		if (!stack.getTagCompound().hasKey("xp"))
		{
			tooltip.add(EnumChatFormatting.GREEN + "0");
		}
		else
		{
			tooltip.add(EnumChatFormatting.GREEN + Integer.toString(stack.getTagCompound().getInteger("xp")));
		}
	}
}