Find the first text descendent node of an element
/*
* 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) {}
}
}
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