Gets the child of the specified XML element having the specified unique name. - Android XML

Android examples for XML:XML Child Element

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Description

Gets the child of the specified XML element having the specified unique name.

Demo Code

/*/*from  w  w w  . ja v  a  2s .  c om*/
 * JBoss, Home of Professional Open Source
 * Copyright 2005, JBoss Inc., and individual contributors as indicated
 * by the @authors tag. See the copyright.txt in the distribution for a
 * full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
//package com.java2s;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import java.util.ArrayList;
import java.util.Iterator;

public class Main {
    /**
     * Gets the child of the specified element having the specified unique
     * name.  If there are more than one children elements with the same name
     * and exception is thrown.
     *
     * @param element    The parent element
     * @param tagName    The name of the desired child
     * @return           The named child.
     *
     * @throws Exception   Child was not found or was not unique.
     */
    public static Element getUniqueChild(Element element, String tagName)
            throws Exception {
        Iterator<Element> goodChildren = getChildrenByTagName(element,
                tagName);

        if (goodChildren != null && goodChildren.hasNext()) {
            Element child = goodChildren.next();
            if (goodChildren.hasNext()) {
                throw new Exception("expected only one " + tagName + " tag");
            }
            return child;
        } else {
            throw new Exception("expected one " + tagName + " tag");
        }
    }

    /**
     * Returns an iterator over the children of the given element with
     * the given tag name.
     *
     * @param element    The parent element
     * @param tagName    The name of the desired child
     * @return           An interator of children or null if element is null.
     */
    public static Iterator<Element> getChildrenByTagName(Element element,
            String tagName) {
        if (element == null)
            return null;
        // getElementsByTagName gives the corresponding elements in the whole 
        // descendance. We want only children

        NodeList children = element.getChildNodes();
        ArrayList<Element> goodChildren = new ArrayList<Element>();
        for (int i = 0; i < children.getLength(); i++) {
            Node currentChild = children.item(i);
            if (currentChild.getNodeType() == Node.ELEMENT_NODE
                    && ((Element) currentChild).getTagName()
                            .equals(tagName)) {
                goodChildren.add((Element) currentChild);
            }
        }
        return goodChildren.iterator();
    }
}

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