/*
 * Copyright 2014 Skynav, Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY SKYNAV, INC. AND ITS CONTRIBUTORS “AS IS” AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL SKYNAV, INC. OR ITS CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package com.skynav.ttv.util;

import java.util.List;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;

public class Traverse {

    private Traverse() {}

    public static void traverseElements(Document document, Visitor v) throws Exception {
        Element root = document.getDocumentElement();
        if (root != null)
            traverseElements(root, null, v);
    }

    public static void traverseElements(Element elt, Element parent, Visitor v) throws Exception {
        if (!v.preVisit(elt, parent))
            return;
        // extract stable (non-live) list of children in case visitors mutate child list
        List<Element> children = new java.util.ArrayList<Element>();
        for (Node node = elt.getFirstChild(); node != null; node = node.getNextSibling()) {
            if (node instanceof Element)
                children.add((Element) node);
        }
        // traverse stable (non-live) list of children
        for (Element child : children) {
            traverseElements(child, elt, v);
        }
        if (!v.postVisit(elt, parent))
            return;
    }

}