KnownNullableImmutableList.java

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// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
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package org.apache.doris.datasource.metacache;

import java.util.AbstractList;
import java.util.Collection;
import java.util.Objects;
import java.util.RandomAccess;

/** Compact immutable list with an exact retained capacity that permits null elements. */
public final class KnownNullableImmutableList<E> extends AbstractList<E> implements RandomAccess {
    private final Object[] elements;

    private KnownNullableImmutableList(Collection<? extends E> values) {
        this.elements = Objects.requireNonNull(values, "values can not be null").toArray();
    }

    public static <E> KnownNullableImmutableList<E> copyOf(Collection<? extends E> values) {
        return new KnownNullableImmutableList<>(values);
    }

    @Override
    @SuppressWarnings("unchecked")
    public E get(int index) {
        return (E) elements[index];
    }

    @Override
    public int size() {
        return elements.length;
    }
}