/*
* Copyright (c) 2017, 2017, 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.
*
* 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
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*/
package org.graalvm.compiler.core.common.util;
import java.util.AbstractList;
import java.util.List;
import java.util.RandomAccess;
/**
* A {@code ReversedList} is a view on an other list with the elements in reverse order.
*
* This implementation is made for {@link RandomAccess} lists.
*/
public class ReversedList<T> extends AbstractList<T> implements RandomAccess {
private final List<T> original;
public ReversedList(List<T> original) {
assert original instanceof RandomAccess;
this.original = original;
}
@Override
public T get(int index) {
return original.get(original.size() - index - 1);
}
@Override
public int size() {
return original.size();
}
/**
* Creates a list that is a view on {@code list} in reverse order.
*/
public static <T> ReversedList<T> reversed(List<T> list) {
return new ReversedList<>(list);
}
}