[1.14.4] Can someone explain to me the correct way of using LazyOptional and some other questions regarding Interfaces

[Samaritans]

Hey, moving from 1.12 to 1.14 modding, looks like capabilities are in a LazyOptional container of some sort. Still a bit confused. I looked at the code in vanilla chest, if my tile with an inventory, would this code be the correct way:

@Override
    public <T> LazyOptional<T> getCapability(net.minecraftforge.common.capabilities.Capability<T> cap, Direction side) {
        if (!this.removed && cap == CapabilityItemHandler.ITEM_HANDLER_CAPABILITY) {
            if (this.potHandler == null) {
                this.potHandler = LazyOptional.of(this::createHandler);
            }
            return this.potHandler.cast();
        }
        return super.getCapability(cap, side);
    }

    private IItemHandlerModifiable createHandler() {
        return new InvWrapper(this);
    }

 

So what if i want a tile with 2 capabilities, Fluid AND Item, would this be correct?

@Nonnull
    @Override
    public <T> LazyOptional<T> getCapability(@Nonnull Capability<T> cap, @Nullable Direction side) {
        if (!this.removed) {
            if (cap == CapabilityItemHandler.ITEM_HANDLER_CAPABILITY) {
                if (this.itemStackHandler == null) {
                    this.itemStackHandler = LazyOptional.of(this::createItemHandler);
                }
                return this.itemStackHandler.cast();
            }
            if (cap == CapabilityFluidHandler.FLUID_HANDLER_CAPABILITY) {
                if (this.fluidHandler == null) {
                    this.fluidHandler = LazyOptional.of(this::createFluidHandler);
                }
                return this.fluidHandler.cast();
            }
        }
        return super.getCapability(cap, side);
    }

    private IItemHandlerModifiable createItemHandler() {
        return new ItemStackHandler(1) {
            @Override
            protected void onContentsChanged(int slot) {
                getWorld().addBlockEvent(getPos(), getBlockState().getBlock(), 1, 0);
                getWorld().notifyNeighborsOfStateChange(getPos(), getBlockState().getBlock());
                markDirty();
            }
        };
    }

    private FluidTank createFluidHandler() {
        return new FluidTank(capacity) {
            @Override
            protected void onContentsChanged() {
                markDirty();
            }
        };
    }

 

Now, if I want a tile that has both item and fluid capabilites, should my tile implement IInventory, IItemHandler, IFluidTank, IFluidHandler, etc. what is even the difference and what do i use? Thanks

[Samaritans]

@diesieben07 So I would do

private final LazyOptional<IItemHandlerModifiable> potHandler = null;

 

And then in get Capability I'm not sure what to do? How do i actually get whats inside the LazyOptional

    @Override
    public <T> LazyOptional<T> getCapability(net.minecraftforge.common.capabilities.Capability<T> cap, Direction side) {
        if (!this.removed && cap == CapabilityItemHandler.ITEM_HANDLER_CAPABILITY) {
          this.potHandler = LazyOptional.of(this::createHandler);
          return this.potHandler.cast();
          // Wouldn't this just be creating new handler all the time?
        }
        return super.getCapability(cap, side);
    }

 

So when i interact with my capability, what would i to do actually get them? Do i do something like

IItemHandler itemStackHandler = te.getCapability(CapabilityItemHandler.ITEM_HANDLER_CAPABILITY, null).orElse(null);

and then check null?

 

Also, what if i want IItemHandlerModifiable, how would I get that capability since it just returns an IItemHandler, can I just straight up cast it?

[Samaritans]

@diesieben07 Ah i see, so would something like this be correct:

CrushingTubTileEntity.java

public class CrushingTubTileEntity extends TileEntity {
    public static int capacity = FluidAttributes.BUCKET_VOLUME * 8;

    public LazyOptional<ItemStackHandler> itemStackHandler = LazyOptional.of(this::createItemHandler);
    public LazyOptional<FluidTank> fluidHandler = LazyOptional.of(this::createFluidHandler);

    public CrushingTubTileEntity() {
        super(ModTileEntityType.CRUSHING_TUB);
    }

    @Override
    public void read(CompoundNBT tag) {
        super.read(tag);
        getFluidHandler().readFromNBT(tag);
        if (tag.contains("items")) {
            getItemHandler().deserializeNBT((CompoundNBT) tag.get("items"));
        }
    }

    @Override
    public CompoundNBT write(CompoundNBT tag) {
        tag = super.write(tag);
        getFluidHandler().writeToNBT(tag);
        tag.put("items", getItemHandler().serializeNBT());
        return tag;
    }

    @Nullable
    @Override
    public SUpdateTileEntityPacket getUpdatePacket() {
        return new SUpdateTileEntityPacket(getPos(), 3, getUpdateTag());
    }

    @Override
    public void onDataPacket(NetworkManager net, SUpdateTileEntityPacket pkt) {
        this.read(pkt.getNbtCompound());
    }

    @Override
    public CompoundNBT getUpdateTag() {
        return this.write(new CompoundNBT());
    }

    @Nonnull
    @Override
    public <T> LazyOptional<T> getCapability(@Nonnull Capability<T> cap, @Nullable Direction side) {
        if (!this.removed) {
            if (cap == CapabilityItemHandler.ITEM_HANDLER_CAPABILITY) {
                return this.itemStackHandler.cast();
            }
            if (cap == CapabilityFluidHandler.FLUID_HANDLER_CAPABILITY) {
                return this.fluidHandler.cast();
            }
        }
        return super.getCapability(cap, side);
    }

    public ItemStackHandler getItemHandler() {
        return itemStackHandler.orElseThrow(RuntimeException::new);
    }

    public FluidTank getFluidHandler() {
        return fluidHandler.orElseThrow(RuntimeException::new);
    }

    private ItemStackHandler createItemHandler() {
        return new ItemStackHandler(1) {
            @Override
            protected void onContentsChanged(int slot) {
                getWorld().addBlockEvent(getPos(), getBlockState().getBlock(), 1, 0);
                getWorld().notifyNeighborsOfStateChange(getPos(), getBlockState().getBlock());
                markDirty();
            }
        };
    }

    private FluidTank createFluidHandler() {
        return new FluidTank(capacity) {
            @Override
            protected void onContentsChanged() {
                markDirty();
            }
        };
    }

 

[Samaritans]

@diesieben07 a little unrelated, but is there any situation tileentity world actually returns null?