Find the first text descendent node of an element : Node « XML « Java Tutorial






/*
 * Copyright (C) 2001  Christian Cryder [christianc@granitepeaks.com]
 *
 * This library 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 library 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 library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * $Id: DOMUtil.java 114 2005-12-09 15:51:51Z christianc $
 */

import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.Iterator;

import org.w3c.dom.Attr;
import org.w3c.dom.CharacterData;
import org.w3c.dom.Comment;
import org.w3c.dom.DOMException;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.Text;

/**
 * DOM related utility functions.
 */
public class DOMUtil {

    private static byte[] sep = System.getProperty("line.separator").getBytes();

    /**
     * Find the first text descendent node of an element.
     * This recursively looks more than one level to search
     * for text in font nodes, etc.
     *
     * @param node The starting node for the search.
     * @return The text node or null if not found.
     */
    public static Text findFirstText(Node node) {
        if (node instanceof Text) return (Text) node;
        for (Node child = node.getFirstChild(); child!=null; child = child.getNextSibling()) {
            Text text = findFirstText(child);
            if (text!=null) return text;
        }
        return null;
    }

    /**
     * Gets the first text descendent node of an element.
     * This recursively looks more than one level to search
     * for text in font nodes, etc. Throws a DOMException
     * if the Text object is not found.
     *
     * @param node The starting node for the search.
     * @return The text node or null if not found.
     * @throws DOMException if the Text object is not found
     */
    public static Text getFirstText(Node node) {
        Text text = findFirstText(node);
        if (text==null) {
            String msg = "No child text mode found for element";
            String id = getID(node);
            throw new DOMException((short) -1, msg+(id!=null ? "; id=\""+id+"\"" : ""));
        }
        return text;
    }



    /**
     * Automatically set text in a Node. Basically we find the first
     * Text node beneath the current node and replace it with a
     * CDATASection for the incoming text. All other Text nodes are
     * removed. Throws a DOMException if it's illegal to add a Text
     * child to the particular node.
     *
     * @param node the starting node for the search.
     * @param text the text to be set
     * @param allowMarkupInText whether to allow markup in text to pass through unparsed
     * @return the updated node
     * @throws DOMException if the Text object is not found
     */
    public static Node setTextInNode(Node node, String text, boolean allowMarkupInText) {
        //start by setting the value in the first text node we find with a comment
        Comment comment = node.getOwnerDocument().createComment("");
        Node newNode = null;
        
        //csc_092701.1 - support both encoded/unencoded text
        if (allowMarkupInText) newNode = node.getOwnerDocument().createCDATASection(text);
        else newNode = node.getOwnerDocument().createTextNode(text);
//System.out.println ("newNode: "+newNode);
        
        Text textComp = DOMUtil.findFirstText((Element) node);
//System.out.println ("textComp:"+textComp);        
        if (textComp==null) {
            node.appendChild(comment);
        } else {
            Node parent = textComp.getParentNode();
            parent.replaceChild(comment, textComp);
        }
        
        //now remove all the rest of the text nodes
        removeAllTextNodes(node);        

        //now replace the comment with the newNode
        Node parent = comment.getParentNode();
        parent.replaceChild(newNode, comment);
//System.out.println ("parent:  "+parent);        
//System.out.println ("result:  "+DOMUtil.findFirstText((Element) parent));        
//DOMUtil.printStackTrace(parent.getOwnerDocument().getDocumentElement());
        return node;
    }
    
    /**
     * Remove all text nodes below this node
     *
     * @param node The starting node for the search.
     */
    public static void removeAllTextNodes(Node node) {
        if (node==null) return;
        if (!node.hasChildNodes()) return;
        NodeList nl = node.getChildNodes();
        for (int i=nl.getLength()-1; i>=0; i--) {
            Node n = (Node) nl.item(i);        
            if (n instanceof Text) node.removeChild(n);
            else removeAllTextNodes(n);
        }
    }
    
    /**
     * Given a Node name, return the "id" attribute if it exists.
     * If it does not exist, return null instead. This is basically
     * just a convenience method to cast the node to element and 
     * return the id from that.
     *
     * @param node the node name in question
     * @return the id value for the given node, if it exists. null if 
     *        doesn't
     */
    public static String getID(Node node) {
        return getID(node, null);
    }

    /**
     * Given a Node, return the "id" attribute if it exists.
     * If it does not exist, return nullResponse instead. This is basically
     * just a convenience method to cast the node to element and 
     * return the id from that.
     *
     * @param node the node in question
     * @param nullResponse the response to be returned if the id attribute
     *        does not exist
     * @return the id value for the given node, if it exists. null if 
     *        doesn't
     */
    public static String getID(Node node, String nullResponse) {
        String nodeName = nullResponse;
        if (node instanceof Element) {
            nodeName = ((Element) node).getAttribute("id");
        }
        return nodeName;
    }



    protected static void print(OutputStream out, String s) {
        if (out!=null) try {
            out.write(s.getBytes());
            out.write(sep);
        } catch (IOException ioe) {}
    }
}








33.29.Node
33.29.1.Add a text node to the element
33.29.2.Add a text node to the beginning of the element
33.29.3.Add a text node before the last child of the element
33.29.4.Add a text node in front of the new item element
33.29.5.Adding a Text Node to a DOM Document
33.29.6.Removing a Node from a DOM Document
33.29.7.Remove All nodes
33.29.8.Get the text node
33.29.9.Change a particular node in XML
33.29.10.Add another element after the first child of the root element
33.29.11.Create a new element and move the middle text node to it
33.29.12.Move all children of the element in front of the element
33.29.13.Split the node at the beginning of the word
33.29.14.Compare two DOM Nodes from JBoss
33.29.15.Convert NodeList To Node Array
33.29.16.Convert node element To String
33.29.17.Search our next siblings for a given node
33.29.18.Search earlier siblings for a given node
33.29.19.Returns a first child DOM Node of type ELEMENT_NODE for the specified Node
33.29.20.Search up the tree for a given node
33.29.21.Get the first text node associated with this element
33.29.22.Simplified implementation of a Node from a Document Object Model (DOM)
33.29.23.Returns a list of value for the given node
33.29.24.Returns the value of the child node with the given name
33.29.25.Remove this node from its parent.
33.29.26.Find the first text descendent node of an element
33.29.27.Copies the source tree into the specified place in a destination tree.
33.29.28.DOM helper for root element
33.29.29.Compare two DOM Nodes