domutils.java

MobilerRPC enables remote procedure calls between J2ME applications and java sevlet server.

/*
 * Copyright (c) 2003, Artem Rudoy
 * 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.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 THE AUTHOR 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 net.sourceforge.mobilerpc;

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

public class DOMUtils
{
    /**
     * Return element's attribute value or <bode>null</code>
     * if attribute does not exist.
     *
     * @return element's attribute value
     * @param element
     * @param attributeName
     */
    public static String getAttributeValue(Element element, String attributeName)
    {
        Attr attribute = element.getAttributeNode(attributeName);
        if(attribute == null)
            return null;
        else
            return attribute.getValue();
    }

    /**
     * Returns the first child element of the specified node
     * with the specified name of null if no child element exists
     *
     * @return the first child element of the specified node
     * @param node
     * @param elementName name of element to find
     */
    public static Element getFirstNamedChildElement(Node node, String elementName)
    {
        Node child = node.getFirstChild();

        while(child != null)
        {
            if(child.getNodeType() == Node.ELEMENT_NODE &&
                    ((Element) child).getTagName().equals(elementName))
                break;
            child = child.getNextSibling();
        }

        return (Element) child;
    }

    /**
     * Returns next sibling element of the specified node
     * with the specified name of null if no sibling
     * element exists
     *
     * @return next sibling element of the specified node
     * @param node
     * @param elementName
     */
    public static Element getNextNamedSiblingElement(Node node, String elementName)
    {
        Node sibling = node.getNextSibling();

        while(sibling != null)
        {
            if(sibling.getNodeType() == Node.ELEMENT_NODE &&
                    ((Element) sibling).getTagName().equals(elementName))
                break;
            sibling = sibling.getNextSibling();
        }

        return (Element) sibling;
    }

    public static String getChildElementValue(Node node, String elementName)
    {
        Element element = getFirstNamedChildElement(node, elementName);
        if(element == null)
            return null;
        StringBuffer value = new StringBuffer();
        for(Node child = element.getFirstChild();
                child != null;
                child = child.getNextSibling())
        {
            if(child.getNodeType() == Node.TEXT_NODE)
                value.append(child.getNodeValue());
            else if(child.getNodeType() == Node.CDATA_SECTION_NODE)
                value.append(child.getNodeValue());
        }
        return value.toString().trim();
    }
}