rev 52889 : 8214023: Update Graal

   1 /*
   2  * Copyright (c) 2017, 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 
  25 package org.graalvm.compiler.core.common.util;
  26 
  27 import java.util.AbstractList;
  28 import java.util.List;
  29 import java.util.RandomAccess;
  30 
  31 /**
  32  * A {@code ReversedList} is a view on an other list with the elements in reverse order.
  33  *
  34  * This implementation is made for {@link RandomAccess} lists.
  35  */
  36 public class ReversedList<T> extends AbstractList<T> implements RandomAccess {
  37     private final List<T> original;
  38 
  39     public ReversedList(List<T> original) {
  40         assert original instanceof RandomAccess;
  41         this.original = original;
  42     }
  43 
  44     @Override
  45     public T get(int index) {
  46         return original.get(original.size() - index - 1);
  47     }
  48 
  49     @Override
  50     public int size() {
  51         return original.size();
  52     }
  53 
  54     /**
  55      * Creates a list that is a view on {@code list} in reverse order.
  56      */
  57     public static <T> ReversedList<T> reversed(List<T> list) {
  58         return new ReversedList<>(list);
  59     }
  60 }
--- EOF ---