public class Coin extends Item {
    private final int[] metadata = new int[]{ 1, 2, 5, 10, 25, 50, 100};
    private final ItemStack[] coinValues;

    public Coin() {
        super(1234);

        coinValues = new ItemStack[metadata.length];
        for (int i = 0; i < metadata.length; i++) {
            coinValues[i] = new ItemStack(this, 1, metadata[i]);
        }
    }

    public void registerRecipes() {
        for (int x : metadata) {
            registerRecipes(x, x, 0, new ItemStack[9]);
        }
    }

    private void registerRecipes(int coin, int left, int index, ItemStack[] recipe) {
        if (left > 0) {
            if (index == 9) {
                return;
            }

            for (int x = 0; x < metadata.length; x++) {
                int v = metadata[x];
                if (v >= recipe[0].getItemDamage() && v < coin) {
                    recipe[index] = coinValues[x];
                    registerRecipes(coin, left-v, index+1, recipe);
                }
            }
        } else if (left == 0) {
            // new CoinRecipe(Arrays.copyOf(stacks, size));
        }
    }
}