[1.13.2] IItemHandler and Capabilities

[Saucier]

I'm trying to setup my tile entity capabilities for automation, but I'm a bit stuck.

I have a tile with an inventory of 4 slots. Two slots (0, 1) for input items from the side and two slots (2, 3) for output items to the bottom. I'm using an ItemStackHandler for my inventory.

private final IItemHandler inv = new ItemStackHandler(4) {
	@Override
	protected void onContentsChanged(int slot) {
		super.onContentsChanged(slot);
		markDirty();
	}
};

 

How would I implement the ITEM_HANDLER_CAPABILITY here?

 

My problem:

- A hopper/pipe that is inserting items should only access slots 0,1 and a hopper/pipe that is extracting items should only access slots 2,3

 

If I'm returning my inv directly, it is returning all 4 slots.

Do I need to separate my ItemStackHandler into two inventories like invInput and invOutput or can I still use one ItemStackHandler and return only half of the inventory at the getCapability method?

Edited April 21, 2019 by Saucier

[V0idWa1k3r]

Use a custom implementation of IItemHandler#insertItem and IItemHandler#extractItem. Both methods give you a slot as a parameter.

If you want extraction/insertion to be based on the side you can return a wrapper around your IItemHandler based on the side that only exposes the slots you want to expose for necessarry operation in getCapability. Note that you would still need to use a custom implementation of IItemHandler#insertItem and IItemHandler#extractItem.

[LTNightshade]

Override TileEntity#hasCapability and TileEntity#getCapability

 

[Cadiboo]

6 hours ago, LTNightshade said:

Override TileEntity#hasCapability and TileEntity#getCapability

This stuff changed in 1.13.2

[Saucier]

On 4/14/2019 at 4:28 AM, V0idWa1k3r said:

Use a custom implementation of IItemHandler#insertItem and IItemHandler#extractItem. Both methods give you a slot as a parameter.

If you want extraction/insertion to be based on the side you can return a wrapper around your IItemHandler based on the side that only exposes the slots you want to expose for necessarry operation in getCapability. Note that you would still need to use a custom implementation of IItemHandler#insertItem and IItemHandler#extractItem.

Thank you. Could you tell me the right way to return my overridden methods at getCapability?

That's what I have so far:

private final IItemHandler inv = new ItemStackHandler(4) {
	@Override
	protected void onContentsChanged(int slot) {
		super.onContentsChanged(slot);
		markDirty();
	}
	
	@Override
	public boolean isItemValid(int slot, @Nonnull ItemStack stack) {
		// My checks to see if an item is valid in the slot
	}
};

private final LazyOptional<IItemHandler> capItemHandler = LazyOptional.of(() -> createCapabilityHandler());

protected IItemHandler createCapabilityHandler() {
	return new CombinedInvWrapper(this.inv) {
		@Override
		public ItemStack insertItem(int slot, @Nonnull ItemStack stack, boolean simulate) {
			// Only insert, if stack is valid for the slot
			return (isItemValid(slot, stack)) ? super.insertItem(slot, stack, simulate) : stack;
		}
			
		@Override
		public ItemStack extractItem(int slot, int amount, boolean simulate) {
			// Only pull items from the output slots
			return (slot == 2 || slot == 3) ? super.extractItem(slot, amount, simulate) : ItemStack.EMPTY;
		}
	};
}

public <T> LazyOptional<T> getCapability(Capability<T> cap, @Nullable EnumFacing side) {
	return CapabilityItemHandler.ITEM_HANDLER_CAPABILITY.orEmpty(cap, capItemHandler);
}

 

It's working so far, but I used the CombinedInvWrapper even tho I'm just using one IItemHandler. I figured I don't need to use different sides, I'll allow inserting/extracting on every side.

Is there any better way to do this or is my attempt fine?

 

Thanks so far.