Code/net/minecraft/core/NonNullList.java

package net.minecraft.core;

import com.google.common.collect.Lists;
import java.util.AbstractList;
import java.util.Arrays;
import java.util.List;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import org.apache.commons.lang3.Validate;

public class NonNullList<E> extends AbstractList<E> {
    private final List<E> list;
    @Nullable
    private final E defaultValue;

    public static <E> NonNullList<E> create() {
        return new NonNullList<>(Lists.newArrayList(), null);
    }

    public static <E> NonNullList<E> createWithCapacity(int p_182648_) {
        return new NonNullList<>(Lists.newArrayListWithCapacity(p_182648_), null);
    }

    public static <E> NonNullList<E> withSize(int p_122781_, E p_122782_) {
        Validate.notNull(p_122782_);
        Object[] aobject = new Object[p_122781_];
        Arrays.fill(aobject, p_122782_);
        return new NonNullList<>(Arrays.asList((E[])aobject), p_122782_);
    }

    @SafeVarargs
    public static <E> NonNullList<E> of(E p_122784_, E... p_122785_) {
        return new NonNullList<>(Arrays.asList(p_122785_), p_122784_);
    }

    protected NonNullList(List<E> p_122777_, @Nullable E p_122778_) {
        this.list = p_122777_;
        this.defaultValue = p_122778_;
    }

    @Nonnull
    @Override
    public E get(int p_122791_) {
        return this.list.get(p_122791_);
    }

    @Override
    public E set(int p_122795_, E p_122796_) {
        Validate.notNull(p_122796_);
        return this.list.set(p_122795_, p_122796_);
    }

    @Override
    public void add(int p_122787_, E p_122788_) {
        Validate.notNull(p_122788_);
        this.list.add(p_122787_, p_122788_);
    }

    @Override
    public E remove(int p_122793_) {
        return this.list.remove(p_122793_);
    }

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

    @Override
    public void clear() {
        if (this.defaultValue == null) {
            super.clear();
        } else {
            for (int i = 0; i < this.size(); i++) {
                this.set(i, this.defaultValue);
            }
        }
    }
}