ReverseJSObjectIterator.java

/*
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 * 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.
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package jdk.nashorn.internal.runtime.arrays;

import jdk.nashorn.api.scripting.JSObject;
import jdk.nashorn.internal.runtime.JSType;

/**
 * Reverse iterator over a ScriptObjectMirror
 */
final class ReverseJSObjectIterator extends JSObjectIterator {

    ReverseJSObjectIterator(final JSObject obj, final boolean includeUndefined) {
        super(obj, includeUndefined);
        this.index = JSType.toUint32(obj.hasMember("length")? obj.getMember("length") : 0) - 1;
    }

    @Override
    public boolean isReverse() {
        return true;
    }

    @Override
    protected boolean indexInArray() {
        return index >= 0;
    }

    @Override
    protected long bumpIndex() {
        return index--;
    }
}