private void storeItem(ItemStack item, boolean removal)
	{
		if (item != null) {
			Integer itemAmount = item.getAmount();
			if (itemAmount != 0) {
				Integer typeId = new Integer(item.getTypeId());
				HashMap<Short, Integer> typeIdContent = content.get(typeId);
				if (typeIdContent == null) {
					content.put(typeId, typeIdContent = new HashMap<Short, Integer>());
				}
				Short durability = item.getDurability();
				Integer amount = typeIdContent.get(durability);
				if (amount == null) {
					amount = 0;
				}
				amount = (removal ? (amount - itemAmount) : (amount + itemAmount));
				if (amount != 0) {
					typeIdContent.put(durability, amount);
				} else {
					typeIdContent.remove(durability);
					if (typeIdContent.isEmpty()) {
						content.remove(typeId);
					}
				}
			}
		}
	}