content: // Protocol Buffers - Google's data interchange format
  // Copyright 2008 Google Inc.  All rights reserved.
  // https://developers.google.com/protocol-buffers/
  //
  // Redistribution and use in source and binary forms, with or without
  // modification, are permitted provided that the following conditions are
  // met:
  //
  //     * Redistributions of source code must retain the above copyright
  // notice, this list of conditions and the following disclaimer.
  //     * Redistributions in binary form must reproduce the above
  // copyright notice, this list of conditions and the following disclaimer
  // in the documentation and/or other materials provided with the
  // distribution.
  //     * Neither the name of Google Inc. nor the names of its
  // contributors may be used to endorse or promote products derived from
  // this software without specific prior written permission.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  package com.google.protobuf;
  
  import com.google.protobuf.Internal.ProtobufList;
  import java.util.ArrayList;
  import java.util.List;
  
  /** Implements {@link ProtobufList} for non-primitive and {@link String} types. */
  final class ProtobufArrayList<E> extends AbstractProtobufList<E> {
  
    private static final ProtobufArrayList<Object> EMPTY_LIST =
        new ProtobufArrayList<Object>(new ArrayList<Object>(0));
  
    static {
      EMPTY_LIST.makeImmutable();
    }
  
    @SuppressWarnings("unchecked") // Guaranteed safe by runtime.
    public static <E> ProtobufArrayList<E> emptyList() {
      return (ProtobufArrayList<E>) EMPTY_LIST;
    }
  
    private final List<E> list;
  
    ProtobufArrayList() {
      this(new ArrayList<E>(DEFAULT_CAPACITY));
    }
  
    private ProtobufArrayList(List<E> list) {
      this.list = list;
    }
  
    @Override
    public ProtobufArrayList<E> mutableCopyWithCapacity(int capacity) {
      if (capacity < size()) {
        throw new IllegalArgumentException();
      }
      List<E> newList = new ArrayList<E>(capacity);
      newList.addAll(list);
      return new ProtobufArrayList<E>(newList);
    }
  
    @Override
    public void add(int index, E element) {
      ensureIsMutable();
      list.add(index, element);
      modCount++;
    }
  
    @Override
    public E get(int index) {
      return list.get(index);
    }
  
    @Override
    public E remove(int index) {
      ensureIsMutable();
      E toReturn = list.remove(index);
      modCount++;
      return toReturn;
    }
  
    @Override
    public E set(int index, E element) {
      ensureIsMutable();
      E toReturn = list.set(index, element);
      modCount++;
      return toReturn;
    }
  
    @Override
    public int size() {
      return list.size();
    }
  }
  