Sword Class MikasOrbit

public class ItemSaphireSword extends ItemSword{

	private static final String TAG_MYTAG = "tag_flyffmc";
	private static final String TAG_PLAYERNAME = "tag_playername";
	private static final String TAG_PLAYERUID = "tag_playeruid";
	private static final String TAG_UPGRADE = "tag_upgrade";
	private static int upgrade = 0;
	private static int range;

	public ItemSaphireSword() {
		super(FlyffMc.saphireToolMaterial);
		this.setUnlocalizedName("saphireSword");
		this.setMaxDamage(2);
	}

	@Override
	public boolean onLeftClickEntity(ItemStack stack, EntityPlayer player, Entity entity) {
		String uid = getNBTTag(stack, TAG_PLAYERUID);
		if (uid.equals("-") && !player.worldObj.isRemote) {
			setNBTData(stack, player);
			return super.onLeftClickEntity(stack, player, entity);
		}
		else if(uid.equals(player.getUniqueID().toString()) && !player.worldObj.isRemote) {
			return super.onLeftClickEntity(stack, player, entity);
		}
		else if (!player.worldObj.isRemote) {
			player.addChatComponentMessage(new ChatComponentText(EnumChatFormatting.RED + "Dieses Item ist Seelengebunden"));
			return true;
		}
		else {
			return true;
		}
	}


	@Override
	public void addInformation(ItemStack stack, EntityPlayer playerIn, List<String> tooltip, boolean advanced) {
		tooltip.add("Dieses Item gehört: " + getNBTTag(stack, TAG_PLAYERNAME));
		if(upgrade >= 1) {
			tooltip.add("Stufe: " + upgrade);
		}
	}

	@Override
	public void onCreated(ItemStack stack, World worldIn, EntityPlayer playerIn) {
		if(!playerIn.worldObj.isRemote) {
			checkUpdate();
			if (getRandomZahl() == 2 && upgrade < 10) {
				addOneToUpgrade();
				setNBTData(stack, playerIn);
			}
//Hier liegt das Problem!
			else {
				stack.setItemDamage(2);
			}
		}
	}

	public static void addOneToUpgrade() {
			upgrade++;
	}

	public int getRandomZahl() {

		int zufallszahl = (int) ((Math.random()*range)+1);
		return zufallszahl;
	}

	public static void checkUpdate() {
		switch (upgrade) {
		case 0:
			range = 2; //50%
			break;
		case 1:
			range = 2; //50%
			break;
		case 2:
			range = 3; //33%
			break;
		case 3:
			range = 3; //33%
			break;
		case 4:
			range = 3; //33%
			break;
		case 5:
			range = 4; //25%
			break;
		case 6:
			range = 4; //25%
			break;
		case 7:
			range = 5; //20%
			break;
		case 8:
			range = 5; //20%
			break;
		case 9:
			range = 6; //17%
			break;
		default:
			break;
		}
	}


	private static void setNBTData(ItemStack stack, EntityPlayer player) {
		NBTTagCompound data = new NBTTagCompound();
		data.setString(TAG_PLAYERNAME, player.getDisplayNameString());
		data.setString(TAG_PLAYERUID, player.getUniqueID().toString());
		data.setInteger(TAG_UPGRADE, upgrade);

		stack.setTagInfo(TAG_MYTAG, data);
	}

	private static String getNBTTag(ItemStack stack, String tag) {
		if(stack.getTagCompound() != null) {
			NBTTagCompound data = stack.getTagCompound().getCompoundTag(TAG_MYTAG);
			return data.getString(tag);
		}
		else {
			return "-";
		}
	}
}