public class ExampleItemBlock extends ItemBlockWithMetadata
{
    public static final String[] SUBNAMES = new String[] {"blue", "green", "yellow", "red"};

    public ExampleItemBlock(Block block)
    {
        super(block, block);
    }

    @Override
    public String getUnlocalizedName(ItemStack itemStack)
    {
        int i = itemStack.getItemDamage();
        if (i < 0 || i >= SUBNAMES.length) i = 0;

        return getUnlocalizedName() + "." + SUBNAMES[i];
    }

}