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