Copyright (c) 2016-present, RxJava Contributors.
Licensed 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
Unless required by applicable law or agreed to in writing, software distributed under the License is
distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
the License for the specific language governing permissions and limitations under the License.
/**
 * Copyright (c) 2016-present, RxJava Contributors.
 *
 * Licensed 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
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License is
 * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
 * the License for the specific language governing permissions and limitations under the License.
 */

package io.reactivex.internal.util;

import java.util.*;
import java.util.concurrent.atomic.AtomicInteger;

Tracks the current underlying array size in a volatile field.
Type parameters:
<T> – the element type
Since:
2.0.7/**
 * Tracks the current underlying array size in a volatile field.
 *
 * @param <T> the element type
 * @since 2.0.7
 */
public final class VolatileSizeArrayList<T> extends AtomicInteger implements List<T>, RandomAccess {

    private static final long serialVersionUID = 3972397474470203923L;

    final ArrayList<T> list;

    public VolatileSizeArrayList() {
        list = new ArrayList<T>();
    }

    public VolatileSizeArrayList(int initialCapacity) {
        list = new ArrayList<T>(initialCapacity);
    }

    @Override
    public int size() {
        return get();
    }

    @Override
    public boolean isEmpty() {
        return get() == 0;
    }

    @Override
    public boolean contains(Object o) {
        return list.contains(o);
    }

    @Override
    public Iterator<T> iterator() {
        return list.iterator();
    }

    @Override
    public Object[] toArray() {
        return list.toArray();
    }

    @Override
    public <E> E[] toArray(E[] a) {
        return list.toArray(a);
    }

    @Override
    public boolean add(T e) {
        boolean b = list.add(e);
        lazySet(list.size());
        return b;
    }

    @Override
    public boolean remove(Object o) {
        boolean b = list.remove(o);
        lazySet(list.size());
        return b;
    }

    @Override
    public boolean containsAll(Collection<?> c) {
        return list.containsAll(c);
    }

    @Override
    public boolean addAll(Collection<? extends T> c) {
        boolean b = list.addAll(c);
        lazySet(list.size());
        return b;
    }

    @Override
    public boolean addAll(int index, Collection<? extends T> c) {
        boolean b = list.addAll(index, c);
        lazySet(list.size());
        return b;
    }

    @Override
    public boolean removeAll(Collection<?> c) {
        boolean b = list.removeAll(c);
        lazySet(list.size());
        return b;
    }

    @Override
    public boolean retainAll(Collection<?> c) {
        boolean b = list.retainAll(c);
        lazySet(list.size());
        return b;
    }

    @Override
    public void clear() {
        list.clear();
        lazySet(0);
    }

    @Override
    public T get(int index) {
        return list.get(index);
    }

    @Override
    public T set(int index, T element) {
        return list.set(index, element);
    }

    @Override
    public void add(int index, T element) {
        list.add(index, element);
        lazySet(list.size());
    }

    @Override
    public T remove(int index) {
        T v = list.remove(index);
        lazySet(list.size());
        return v;
    }

    @Override
    public int indexOf(Object o) {
        return list.indexOf(o);
    }

    @Override
    public int lastIndexOf(Object o) {
        return list.lastIndexOf(o);
    }

    @Override
    public ListIterator<T> listIterator() {
        return list.listIterator();
    }

    @Override
    public ListIterator<T> listIterator(int index) {
        return list.listIterator(index);
    }

    @Override
    public List<T> subList(int fromIndex, int toIndex) {
        return list.subList(fromIndex, toIndex);
    }

    @Override
    public boolean equals(Object obj) {
        if (obj instanceof VolatileSizeArrayList) {
            return list.equals(((VolatileSizeArrayList<?>)obj).list);
        }
        return list.equals(obj);
    }

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

    @Override
    public String toString() {
        return list.toString();
    }
}