Java XML Element Children getSubelementString(final Element element, final String name)

Description

Locate a sub-element tagged 'name', return its value.

License

Open Source License

Parameter

Parameter	Description
element	Element where to start looking.
name	Name of sub-element to locate.

Exception

Parameter	Description
Exception	when nothing found

Return

Returns string that was found

Declaration

public static final String getSubelementString(final Element element, final String name) throws Exception 

Method Source Code

//package com.java2s;
/*******************************************************************************
 * Copyright (c) 2011 Oak Ridge National Laboratory.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * The scan engine idea is based on the "ScanEngine" developed
 * by the Software Services Group (SSG),  Advanced Photon Source,
 * Argonne National Laboratory,// ww w  . j a  va 2s .  c  om
 * Copyright (c) 2011 , UChicago Argonne, LLC.
 *
 * This implementation, however, contains no SSG "ScanEngine" source code
 * and is not endorsed by the SSG authors.
 ******************************************************************************/

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

public class Main {
    /** Locate a sub-element tagged 'name', return its value.
     *
     *  <p>Will only go one level down, not search the whole tree.
     *
     *  @param element Element where to start looking. May be null.
     *  @param name Name of sub-element to locate.
     *  @param default_value Default value if not found
     *
     *  @return Returns string that was found or default_value.
     */
    public static final String getSubelementString(final Element element, final String name,
            final String default_value) {
        if (element == null)
            return default_value;
        Node n = element.getFirstChild();
        n = findFirstElementNode(n, name);
        if (n == null)
            return default_value;
        // <name> has been found.
        // If it's an empty node, <name/>, that's treated as a value of "".
        // If the node wasn't there at all, the default would have been returned.
        Node text_node = n.getFirstChild();
        if (text_node == null)
            return "";
        return text_node.getNodeValue();
    }

    /** Locate a sub-element tagged 'name', return its value.
     *
     *  <p>Will only go one level down, not search the whole tree.
     *
     *  @param element Element where to start looking.
     *  @param name Name of sub-element to locate.
     *
     *  @return Returns string that was found
     *  @throws Exception when nothing found
     */
    public static final String getSubelementString(final Element element, final String name) throws Exception {
        if (element == null)
            throw new Exception("Missing '" + name + "'");
        Node n = element.getFirstChild();
        n = findFirstElementNode(n, name);
        if (n == null)
            throw new Exception("Missing '" + name + "'");
        // <name>...</name> has been found, but it might be empty: <name/>
        final Node text_node = n.getFirstChild();
        if (text_node == null)
            return "";
        return text_node.getNodeValue();
    }

    /** Look for Element node of given name.
     *
     *  <p>Checks the node and its siblings.
     *  Does not descent down the 'child' links.
     *  @param node Node where to start.
     *  @param name Name of the nodes to look for.
     *  @return Returns node or the next matching sibling or null.
     */
    public static final Element findFirstElementNode(Node node, final String name) {
        while (node != null) {
            if (node.getNodeType() == Node.ELEMENT_NODE && node.getNodeName().equals(name))
                return (Element) node;
            node = node.getNextSibling();
        }
        return null;
    }
}

Related

1. getSubElement(Element ele, String tagName)
2. getSubElement(Element element, String subTagName)
3. getSubelementBoolean(final Element element, final String element_name, final boolean default_value)
4. getSubelementDouble(final Element element, final String element_name)
5. getSubelementDouble(final Element element, final String name, final double default_value)
6. getSubelementString(final Element element, final String name)
7. getSubelementString(final Element element, final String name, final String default_value)
8. getSubelementStrings(final Element element, final String name)
9. getSubelementText(Element element, String subelementName)