minecraft-src/net/minecraft/world/SimpleContainer.java

package net.minecraft.world;

import com.google.common.collect.Lists;
import java.util.List;
import java.util.stream.Collectors;
import net.minecraft.core.HolderLookup;
import net.minecraft.core.NonNullList;
import net.minecraft.nbt.ListTag;
import net.minecraft.world.entity.player.Player;
import net.minecraft.world.entity.player.StackedItemContents;
import net.minecraft.world.inventory.StackedContentsCompatible;
import net.minecraft.world.item.Item;
import net.minecraft.world.item.ItemStack;
import org.jetbrains.annotations.Nullable;

public class SimpleContainer implements Container, StackedContentsCompatible {
	private final int size;
	private final NonNullList<ItemStack> items;
	@Nullable
	private List<ContainerListener> listeners;

	public SimpleContainer(int size) {
		this.size = size;
		this.items = NonNullList.withSize(size, ItemStack.EMPTY);
	}

	public SimpleContainer(ItemStack... items) {
		this.size = items.length;
		this.items = NonNullList.of(ItemStack.EMPTY, items);
	}

	/**
	 * Add a listener that will be notified when any item in this inventory is modified.
	 */
	public void addListener(ContainerListener listener) {
		if (this.listeners == null) {
			this.listeners = Lists.<ContainerListener>newArrayList();
		}

		this.listeners.add(listener);
	}

	/**
	 * Removes the specified {@link net.minecraft.world.ContainerListener} from receiving further change notices.
	 */
	public void removeListener(ContainerListener listener) {
		if (this.listeners != null) {
			this.listeners.remove(listener);
		}
	}

	@Override
	public ItemStack getItem(int slot) {
		return slot >= 0 && slot < this.items.size() ? this.items.get(slot) : ItemStack.EMPTY;
	}

	public List<ItemStack> removeAllItems() {
		List<ItemStack> list = (List<ItemStack>)this.items.stream().filter(itemStack -> !itemStack.isEmpty()).collect(Collectors.toList());
		this.clearContent();
		return list;
	}

	@Override
	public ItemStack removeItem(int slot, int amount) {
		ItemStack itemStack = ContainerHelper.removeItem(this.items, slot, amount);
		if (!itemStack.isEmpty()) {
			this.setChanged();
		}

		return itemStack;
	}

	public ItemStack removeItemType(Item item, int amount) {
		ItemStack itemStack = new ItemStack(item, 0);

		for (int i = this.size - 1; i >= 0; i--) {
			ItemStack itemStack2 = this.getItem(i);
			if (itemStack2.getItem().equals(item)) {
				int j = amount - itemStack.getCount();
				ItemStack itemStack3 = itemStack2.split(j);
				itemStack.grow(itemStack3.getCount());
				if (itemStack.getCount() == amount) {
					break;
				}
			}
		}

		if (!itemStack.isEmpty()) {
			this.setChanged();
		}

		return itemStack;
	}

	public ItemStack addItem(ItemStack stack) {
		if (stack.isEmpty()) {
			return ItemStack.EMPTY;
		} else {
			ItemStack itemStack = stack.copy();
			this.moveItemToOccupiedSlotsWithSameType(itemStack);
			if (itemStack.isEmpty()) {
				return ItemStack.EMPTY;
			} else {
				this.moveItemToEmptySlots(itemStack);
				return itemStack.isEmpty() ? ItemStack.EMPTY : itemStack;
			}
		}
	}

	public boolean canAddItem(ItemStack stack) {
		boolean bl = false;

		for (ItemStack itemStack : this.items) {
			if (itemStack.isEmpty() || ItemStack.isSameItemSameComponents(itemStack, stack) && itemStack.getCount() < itemStack.getMaxStackSize()) {
				bl = true;
				break;
			}
		}

		return bl;
	}

	@Override
	public ItemStack removeItemNoUpdate(int slot) {
		ItemStack itemStack = this.items.get(slot);
		if (itemStack.isEmpty()) {
			return ItemStack.EMPTY;
		} else {
			this.items.set(slot, ItemStack.EMPTY);
			return itemStack;
		}
	}

	@Override
	public void setItem(int slot, ItemStack stack) {
		this.items.set(slot, stack);
		stack.limitSize(this.getMaxStackSize(stack));
		this.setChanged();
	}

	@Override
	public int getContainerSize() {
		return this.size;
	}

	@Override
	public boolean isEmpty() {
		for (ItemStack itemStack : this.items) {
			if (!itemStack.isEmpty()) {
				return false;
			}
		}

		return true;
	}

	@Override
	public void setChanged() {
		if (this.listeners != null) {
			for (ContainerListener containerListener : this.listeners) {
				containerListener.containerChanged(this);
			}
		}
	}

	@Override
	public boolean stillValid(Player player) {
		return true;
	}

	@Override
	public void clearContent() {
		this.items.clear();
		this.setChanged();
	}

	@Override
	public void fillStackedContents(StackedItemContents stackedItemContents) {
		for (ItemStack itemStack : this.items) {
			stackedItemContents.accountStack(itemStack);
		}
	}

	public String toString() {
		return ((List)this.items.stream().filter(itemStack -> !itemStack.isEmpty()).collect(Collectors.toList())).toString();
	}

	private void moveItemToEmptySlots(ItemStack stack) {
		for (int i = 0; i < this.size; i++) {
			ItemStack itemStack = this.getItem(i);
			if (itemStack.isEmpty()) {
				this.setItem(i, stack.copyAndClear());
				return;
			}
		}
	}

	private void moveItemToOccupiedSlotsWithSameType(ItemStack stack) {
		for (int i = 0; i < this.size; i++) {
			ItemStack itemStack = this.getItem(i);
			if (ItemStack.isSameItemSameComponents(itemStack, stack)) {
				this.moveItemsBetweenStacks(stack, itemStack);
				if (stack.isEmpty()) {
					return;
				}
			}
		}
	}

	private void moveItemsBetweenStacks(ItemStack stack, ItemStack other) {
		int i = this.getMaxStackSize(other);
		int j = Math.min(stack.getCount(), i - other.getCount());
		if (j > 0) {
			other.grow(j);
			stack.shrink(j);
			this.setChanged();
		}
	}

	public void fromTag(ListTag tag, HolderLookup.Provider levelRegistry) {
		this.clearContent();
		tag.compoundStream().flatMap(compoundTag -> ItemStack.parse(levelRegistry, compoundTag).stream()).forEach(this::addItem);
	}

	public ListTag createTag(HolderLookup.Provider levelRegistry) {
		ListTag listTag = new ListTag();

		for (int i = 0; i < this.getContainerSize(); i++) {
			ItemStack itemStack = this.getItem(i);
			if (!itemStack.isEmpty()) {
				listTag.add(itemStack.save(levelRegistry));
			}
		}

		return listTag;
	}

	public NonNullList<ItemStack> getItems() {
		return this.items;
	}
}