ReverseJSObjectIterator.java revision 953:221a84ef44c0 
1/*
2 * Copyright (c) 2010, 2013, 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.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package jdk.nashorn.internal.runtime.arrays;
27
28import jdk.nashorn.api.scripting.JSObject;
29import jdk.nashorn.internal.runtime.JSType;
30
31/**
32 * Reverse iterator over a ScriptObjectMirror
33 */
34final class ReverseJSObjectIterator extends JSObjectIterator {
35
36    ReverseJSObjectIterator(final JSObject obj, final boolean includeUndefined) {
37        super(obj, includeUndefined);
38        this.index = JSType.toUint32(obj.hasMember("length")? obj.getMember("length") : 0) - 1;
39    }
40
41    @Override
42    public boolean isReverse() {
43        return true;
44    }
45
46    @Override
47    protected boolean indexInArray() {
48        return index >= 0;
49    }
50
51    @Override
52    protected long bumpIndex() {
53        return index--;
54    }
55}
56
57