| /* |
| * Copyright (c) 2003, 2014, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| package sun.swing; |
| |
| import java.util.*; |
| |
| /** |
| * <b>WARNING:</b> This class is an implementation detail and is only |
| * public so that it can be used by two packages. You should NOT consider |
| * this public API. |
| * <p> |
| * <b>WARNING 2:</b> This is not a general purpose List implementation! It |
| * has a specific use and will not work correctly if you use it outside of |
| * its use. |
| * <p> |
| * A specialized ArrayList that caches its hashCode as well as overriding |
| * equals to avoid creating an Iterator. This class is useful in scenarios |
| * where the list won't change and you want to avoid the overhead of hashCode |
| * iterating through the elements invoking hashCode. This also assumes you'll |
| * only ever compare a BakedArrayList to another BakedArrayList. |
| * |
| * @author Scott Violet |
| */ |
| @SuppressWarnings("serial") // JDK-implementation class |
| public class BakedArrayList<E> extends ArrayList<E> { |
| /** |
| * The cached hashCode. |
| */ |
| private int _hashCode; |
| |
| public BakedArrayList(int size) { |
| super(size); |
| } |
| |
| public BakedArrayList(java.util.List<? extends E> data) { |
| this(data.size()); |
| for (int counter = 0, max = data.size(); counter < max; counter++){ |
| add(data.get(counter)); |
| } |
| cacheHashCode(); |
| } |
| |
| /** |
| * Caches the hash code. It is assumed you won't modify the list, or that |
| * if you do you'll call cacheHashCode again. |
| */ |
| public void cacheHashCode() { |
| _hashCode = 1; |
| for (int counter = size() - 1; counter >= 0; counter--) { |
| _hashCode = 31 * _hashCode + get(counter).hashCode(); |
| } |
| } |
| |
| public int hashCode() { |
| return _hashCode; |
| } |
| |
| public boolean equals(Object o) { |
| @SuppressWarnings("unchecked") |
| BakedArrayList<E> list = (BakedArrayList)o; |
| int size = size(); |
| |
| if (list.size() != size) { |
| return false; |
| } |
| while (size-- > 0) { |
| if (!get(size).equals(list.get(size))) { |
| return false; |
| } |
| } |
| return true; |
| } |
| } |