How to get block entity data?

[Gulg]

How can I get block entity data by position (1.18.1)?

Edited April 13, 2022 by Gulg

[Draco18s]

Blocks don't have NBT data.

[Gulg]

Оh, sorry I meant block entity data.

[Luis_ST]

what data are you talking about, since there is a lot of data in a BE?

[Gulg]

I am talking about container items.

[Luis_ST]

you can use BaseContainerBlockEntity#getCapability with CapabilityItemHandler.ITEM_HANDLER_CAPABILITY as parameter
to get the Container of the BE as an IItemHandler

[Gulg]

But I need to get BE before. I have only position.

[Luis_ST]

you can not get the data of a BE without having a Level,
where did you need the BE data? show your code

[Gulg]

	public static <T extends BlockEntity> void tick(Level level, BlockPos pos, BlockState state, T be) {
        if (level.isClientSide()) return;
        // I want to get other BE by position which I have in other variable (otherPos)
    }

 

[Luis_ST]

you have there a Level, so you be able to get them via Level#getBlockEntity

[Gulg]

It always returns null.

[Luis_ST]

29 minutes ago, Gulg said:

It always returns null.

what?

[Gulg]

BlockEntity otherBE = level.getBlockEntity(blockEntityPos);

otherBE always null.

Edited April 14, 2022 by Gulg

[Luis_ST]

is the position load?

[OutCraft]

Hi!

otherBE will return null in two cases:

1. as Luis_ST already said if the position is not loaded ( not in "render distance")

2. The block doesn't have a BlockEntitiy. You can find out if it has one by running the command /data get block <x> <y> <z> in-game. Blocks that have a BlockEntitiy are Containers, Command Blocks, Beehives, Signs and everything else that stores information without a blockstate

[Gulg]

The position is loaded and block has BlockEntity (chest). But it returns null.

[Luis_ST]

this is not possible, please show the full code

[Gulg]

package com.gulgdev.mechanism.block.custom;

import com.gulgdev.mechanism.block.ModBlocks;
import net.minecraft.client.Minecraft;
import net.minecraft.core.BlockPos;
import net.minecraft.core.Direction;
import net.minecraft.network.chat.TextComponent;
import net.minecraft.world.entity.Entity;
import net.minecraft.world.entity.Mob;
import net.minecraft.world.item.ItemStack;
import net.minecraft.world.level.Level;
import net.minecraft.world.level.block.BaseEntityBlock;
import net.minecraft.world.level.block.Block;
import net.minecraft.world.level.block.ChestBlock;
import net.minecraft.world.level.block.Blocks;
import net.minecraft.world.level.block.entity.BlockEntity;
import net.minecraft.world.level.block.state.BlockState;
import net.minecraft.world.level.block.state.properties.BlockStateProperties;
import net.minecraft.world.phys.AABB;
import net.minecraft.world.phys.Vec3;
import net.minecraftforge.items.ItemStackHandler;
import oshi.util.tuples.Pair;

import java.lang.reflect.InvocationTargetException;
import java.util.*;

import static java.lang.Math.abs;

public class MotorBlockEntity extends BlockEntity {
    public static final int movingLimit = 8;
    public static final List<Block> nonMovable = Arrays.asList(
            Blocks.BEDROCK,
            Blocks.OBSIDIAN
    );

    public final ItemStackHandler items;

    public MotorBlockEntity(BlockPos pos, BlockState state) {
        super(ModBlocks.MOTOR_BLOCK_ENTITY.get(), pos, state);

        items = new ItemStackHandler(4) {
            @Override
            public ItemStack extractItem(int slot, int amount, boolean simulate) {
                return super.extractItem(slot, amount, simulate);
            }

            @Override
            public ItemStack insertItem(int slot, ItemStack stack, boolean simulate) {
                return super.insertItem(slot, stack, simulate);
            }
        };
    }

    public static <T extends BlockEntity> void tick(Level level, BlockPos pos, BlockState state, T be) {
        if (level.isClientSide()) return;
        new Thread(() -> {
            MotorBlockEntity entity = (MotorBlockEntity) be;

            Map<BlockPos, Pair<BlockState, BlockEntity>> blocks = FindStructureBlocks(level, pos, movingLimit);
            Map<BlockPos, BlockPos> moving = GetMovingMap(level, blocks, Direction.UP);//state.getValue(BlockStateProperties.FACING));
            if (moving == null) return;

            MoveStructure(level, pos, movingLimit, blocks, moving, true);
        }).start();
    }

    private static Map<BlockPos, Pair<BlockState, BlockEntity>> FindStructureBlocks(Level level, BlockPos start, int limit) {
        Map<BlockPos, Pair<BlockState, BlockEntity>> blocks = new HashMap<BlockPos, Pair<BlockState, BlockEntity>>();
        blocks.put(start, new Pair<BlockState, BlockEntity>(level.getBlockState(start), level.getBlockEntity(start)));
        for (Direction direction : Direction.values()) {
            FindingBranch(level, blocks, start, start, direction, limit);
        }
        return blocks;
    }
    private static void FindingBranch(Level level, Map<BlockPos, Pair<BlockState, BlockEntity>> blocks, BlockPos center, BlockPos start, Direction direction, int limit) {
        BlockPos pos = start.relative(direction);
        if (!(level.getBlockState(pos).isAir() || nonMovable.contains(level.getBlockState(pos).getBlock()) ||
                abs(center.getX() - pos.getX()) >= limit ||
                abs(center.getY() - pos.getY()) >= limit ||
                abs(center.getZ() - pos.getZ()) >= limit)) {
            try {
                Minecraft.getInstance().player.chat(level.getBlockEntity(pos).serializeNBT().toString());
            } catch (NullPointerException e) {
                Minecraft.getInstance().player.chat("no nbt at " + pos.toString());
            }
            blocks.put(pos, new Pair<BlockState, BlockEntity>(level.getBlockState(pos), level.getBlockEntity(pos)));
            for (Direction dir : Direction.values()) {
                if (!blocks.containsKey(pos.relative(dir))) {
                    FindingBranch(level, blocks, center, pos, dir, limit);
                }
            }
        }
    }

    private static Map<BlockPos, BlockPos> GetMovingMap(Level level, Map<BlockPos, Pair<BlockState, BlockEntity>> blocks, Direction direction) {
        Map<BlockPos, BlockPos> moving = new HashMap<BlockPos, BlockPos>();
        for (BlockPos position : blocks.keySet()) {
            BlockPos target = position.relative(direction);
            if (!level.getBlockState(target).isAir() && !blocks.containsKey(target)) return null;
            moving.put(position, target);
        }
        return moving;
    }

    private static void UpdateBlocks(Level level, BlockPos[] blocks) {
        for (BlockPos block : blocks) {
            BlockState state = level.getBlockState(block);
            if (state.getMaterial().isSolid())
                level.sendBlockUpdated(block, state, state, 0);
        }
        for (BlockPos block : blocks) {
            BlockState state = level.getBlockState(block);
            if (!state.getMaterial().isSolid())
                level.sendBlockUpdated(block, state, state, 0);
        }
    }
    private static void ClearStructure(Level level, Map<BlockPos, Pair<BlockState, BlockEntity>> blocks) {
        for (BlockPos pos : blocks.keySet()) {
            level.setBlock(pos, Blocks.AIR.defaultBlockState(), 0);
        }
        UpdateBlocks(level, blocks.keySet().toArray(new BlockPos[0]));
    }
    private static void MoveStructure(Level level, BlockPos center, int limit, Map<BlockPos, Pair<BlockState, BlockEntity>> blocks, Map<BlockPos, BlockPos> moving, boolean moveEntities) {
        ClearStructure(level, blocks);
        List<Entity> entities = null;
        if (moveEntities) {
            entities = level.getEntities(null, AABB.ofSize(new Vec3(center.getX(), center.getY(), center.getZ()), limit * 2 + 1, limit * 2 + 1, limit * 2 + 1));
        }
        for (Map.Entry<BlockPos, Pair<BlockState, BlockEntity>> entry : blocks.entrySet()) {
            BlockPos from = entry.getKey();
            BlockPos to = moving.get(from);
            BlockState blockState = entry.getValue().getA();
            BlockEntity blockEntity = entry.getValue().getB();

            if (moveEntities) {
                for (Entity entity : entities) {
                    if (to.getX() == entity.getBlockX() && from.getY() + 1 == entity.getBlockY() && to.getZ() == entity.getBlockZ()) {
                        entity.moveTo(new Vec3(to.getX(), to.getY() + 1, to.getZ()));
                    }
                }
            }

            if (blockState.getMaterial().isSolid()) {
                level.setBlock(to, blockState, 0);
                try {
                    BlockEntity be = blockEntity.getClass().getConstructor().newInstance(new Object[] { to, blockState });
                    be.deserializeNBT(blockEntity.serializeNBT());
                    level.setBlockEntity(be);
                } catch (InstantiationException | IllegalAccessException | InvocationTargetException | NoSuchMethodException | NullPointerException e) {
                    e.printStackTrace();
                }
            }
        }
        for (Map.Entry<BlockPos, Pair<BlockState, BlockEntity>> entry : blocks.entrySet()) {
            BlockPos from = entry.getKey();
            BlockPos to = moving.get(from);
            BlockState blockState = entry.getValue().getA();
            BlockEntity blockEntity = entry.getValue().getB();

            if (!blockState.getMaterial().isSolid()) {
                level.setBlock(to, blockState, 0);
                try {
                    BlockEntity be = blockEntity.getClass().getConstructor().newInstance(new Object[] { to, blockState });
                    Minecraft.getInstance().player.chat(blockEntity.serializeNBT().toString());
                    be.deserializeNBT(blockEntity.serializeNBT());
                    level.setBlockEntity(be);
                } catch (NullPointerException | InstantiationException | IllegalAccessException | InvocationTargetException | NoSuchMethodException e) {
                    e.printStackTrace();
                }
            }
        }
        UpdateBlocks(level, moving.values().toArray(new BlockPos[0]));
    }
}

 

[Luis_ST]

4 hours ago, Gulg said:

        new Thread(() -> {
			...
        }).start();

why on earth are you create there a new Thread,
the most vanilla code is not thread safe thats why your BlockEntity is null

4 hours ago, Gulg said:

            try {
                Minecraft.getInstance().player.chat(level.getBlockEntity(pos).serializeNBT().toString());
            } catch (NullPointerException e) {
                Minecraft.getInstance().player.chat("no nbt at " + pos.toString());
            }

this will also throw an Exception since you mix up server and client stuff, the Minecraft class is client only so you can not use it there,
if you want to debug your code (because it looks like it) you should use a Logger

last but not least you should use the Java Naming Conventions (method names)

Edited April 14, 2022 by Luis_ST

[Gulg]

Ok, thank you very much.