CoreDoubleCrop

public abstract class CoreDoubleCrop extends CoreCrop
{
    public static final PropertyEnum<EnumCropHalf> HALF = PropertyEnum.<EnumCropHalf>create("half", EnumCropHalf.class);

    public CoreDoubleCrop(String name)
    {
        super(name);

        setDefaultState(withProperties(0, EnumCropHalf.LOWER));
    }

    @Override
    public void updateTick(World world, BlockPos pos, IBlockState state, Random rand)
    {
        if(!world.isAreaLoaded(pos, 1))
            return; // Forge: prevent loading unloaded chunks when checking neighbor's light

        if(getHalf(state) == EnumCropHalf.UPPER)
            return;

        if(world.getLightFromNeighbors(pos.up().up()) >= 9)
        {
            int i = getAge(state);

            if (i < getMaxAge())
            {
                float f = getGrowthChance(this, world, pos);

                if(ForgeHooks.onCropsGrowPre(world, pos, state, rand.nextInt((int) (25.0F / f) + 1) == 0))
                {
                    boolean lower = world.setBlockState(pos, withProperties(i + 1, EnumCropHalf.LOWER), 2);
                    boolean upper = world.setBlockState(pos.up(), withProperties(i + 1, EnumCropHalf.UPPER), 2);
                    System.out.println("updateTick: lower = " + lower + ", upper = " + upper);
                    ForgeHooks.onCropsGrowPost(world, pos, state, world.getBlockState(pos));
                }
            }
        }
    }

    @Override
    public void grow(World world, BlockPos pos, IBlockState state)
    {
        if(getHalf(state) == EnumCropHalf.UPPER)
            return;

        int i = getAge(state) + getBonemealAgeIncrease(world);
        int j = getMaxAge();

        if(i > j)
            i = j;

        boolean lower = world.setBlockState(pos, withProperties(i, EnumCropHalf.LOWER), 2);
        boolean upper = world.setBlockState(pos.up(), withProperties(i, EnumCropHalf.UPPER), 2);
        System.out.println("grow: lower = " + lower + ", upper = " + upper);
    }

    @Override
    public void getDrops(NonNullList<ItemStack> drops, IBlockAccess world, BlockPos pos, IBlockState state, int fortune)
    {
        if(getHalf(state) == EnumCropHalf.UPPER)
        {
            drops.clear();
            return;
        }

        super.getDrops(drops, world, pos, state, 0);

        int age = getAge(state);
        Random rand = world instanceof World ? ((World) world).rand : new Random();

        if(age >= getMaxAge())
        {
            int k = 3 + fortune;

            for(int i = 0; i < 3 + fortune; ++i)
            {
                if(rand.nextInt(2 * getMaxAge()) <= age)
                    drops.add(new ItemStack(this.getSeed(), 1, 0));
            }
        }
    }

    @Override
    public void dropBlockAsItemWithChance(World world, BlockPos pos, IBlockState state, float chance, int fortune)
    {
        if(getHalf(state) == EnumCropHalf.UPPER)
            return;

        super.dropBlockAsItemWithChance(world, pos, state, chance, fortune);

        if(false && !world.isRemote) // Forge: NOP all this.
        {
            int i = getAge(state);

            if(i >= getMaxAge())
            {
                int j = 3 + fortune;

                for(int k = 0; k < j; ++k)
                {
                    if(world.rand.nextInt(2 * getMaxAge()) <= i)
                        spawnAsEntity(world, pos, new ItemStack(getSeed()));
                }
            }
        }
    }

    @Override
    public Item getItemDropped(IBlockState state, Random rand, int fortune)
    {
        if(getHalf(state) == EnumCropHalf.UPPER)
            return Items.AIR;

        return isMaxAge(state) ? getCrop() : getSeed();
    }

    @Override
    public ItemStack getItem(World world, BlockPos pos, IBlockState state)
    {
        return new ItemStack(getSeed());
    }

    @Override
    public void harvestBlock(World world, EntityPlayer player, BlockPos pos, IBlockState state, TileEntity te, ItemStack stack)
    {
        if(getHalf(state) == EnumCropHalf.UPPER)
             world.destroyBlock(pos.down(), true);
        else if(getHalf(state) == EnumCropHalf.LOWER)
            world.setBlockToAir(pos.up());

        super.harvestBlock(world, player, pos, state, te, stack);
    }

    @Override
    public boolean canBlockStay(World world, BlockPos pos, IBlockState state)
    {
        if(state.getBlock() != this)
            return super.canBlockStay(world, pos, state); //Forge: This function is called during world gen and placement, before this block is set, so if we are not 'here' then assume it's the pre-check.

        if(getHalf(state) == EnumCropHalf.UPPER)
            return world.getBlockState(pos.down()).getBlock() == this;
        else
            return world.getBlockState(pos.up()).getBlock() == this;
    }

    @Override
    public boolean canPlaceBlockAt(World world, BlockPos pos)
    {
        return super.canPlaceBlockAt(world, pos) && world.isAirBlock(pos.up());
    }

    @Override
    public void onBlockAdded(World world, BlockPos pos, IBlockState state)
    {
        if(getHalf(state) == EnumCropHalf.LOWER)
            world.setBlockState(pos.up(), getDefaultState().withProperty(HALF, EnumCropHalf.UPPER), 2);
    }

    @Override
    public boolean canGrow(World world, BlockPos pos, IBlockState state, boolean isClient)
    {
        return !isMaxAge(state);
    }

    @Override
    public boolean canUseBonemeal(World world, Random rand, BlockPos pos, IBlockState state)
    {
        return getHalf(state) == EnumCropHalf.LOWER;
    }

    @Override
    public void grow(World world, Random rand, BlockPos pos, IBlockState state)
    {
        if(getHalf(state) == EnumCropHalf.LOWER)
            grow(world, pos, state);
    }

    @Override
    public IBlockState getStateFromMeta(int meta)
    {
        int age = meta % 10;
        EnumCropHalf half = meta >= 10 ? EnumCropHalf.LOWER : EnumCropHalf.UPPER;

        return withProperties(age, half);
    }

    @Override
    public int getMetaFromState(IBlockState state)
    {
        int meta = getAge(state);

        if(getHalf(state) == EnumCropHalf.LOWER)
            meta += 10;

        return meta;
    }

    protected PropertyEnum<EnumCropHalf> getHalfProperty()
    {
        return HALF;
    }

    protected EnumCropHalf getHalf(IBlockState state)
    {
        return state.getValue(getHalfProperty());
    }

    public IBlockState withProperties(int age, EnumCropHalf half)
    {
        return getDefaultState().withProperty(getAgeProperty(), Integer.valueOf(age)).withProperty(getHalfProperty(), half);
    }

    @Override
    public abstract AxisAlignedBB getBoundingBox(IBlockState state, IBlockAccess source, BlockPos pos);

    protected abstract PropertyInteger getAgeProperty();

    @Override
    protected abstract BlockStateContainer createBlockState();

    public static enum EnumCropHalf implements IStringSerializable
    {
        UPPER,
        LOWER;

        public String toString()
        {
            return this.getName();
        }

        public String getName()
        {
            return this == UPPER ? "upper" : "lower";
        }
    }
}