DOMUtil


1   /*
2    * Copyright (C) 2001  Christian Cryder [christianc@granitepeaks.com]
3    *
4    * This library is free software; you can redistribute it and/or
5    * modify it under the terms of the GNU Lesser General Public
6    * License as published by the Free Software Foundation; either
7    * version 2.1 of the License, or (at your option) any later version.
8    *
9    * This library is distributed in the hope that it will be useful,
10   * but WITHOUT ANY WARRANTY; without even the implied warranty of
11   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12   * Lesser General Public License for more details.
13   *
14   * You should have received a copy of the GNU Lesser General Public
15   * License along with this library; if not, write to the Free Software
16   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
17   *
18   * $Id: DOMUtil.java,v 1.11 2004/01/29 18:02:35 christianc Exp $
19   */
20  package org.enhydra.barracuda.core.util.dom;
21  
22  import java.io.*;
23  import java.util.*;
24  import org.w3c.dom.*;
25  
26  import org.enhydra.barracuda.core.util.*;
27  import org.enhydra.barracuda.plankton.*;
28  
29  /**
30   * DOM related utility functions.
31   */
32  public class DOMUtil {
33  
34      private static byte[] sep = System.getProperty("line.separator").getBytes();
35  
36      /**
37       * Find the first text descendent node of an element.
38       * This recursively looks more than one level to search
39       * for text in font nodes, etc.
40       *
41       * @param node The starting node for the search.
42       * @return The text node or null if not found.
43       */
44      public static Text findFirstText(Node node) {
45          if (node instanceof Text) return (Text) node;
46          for (Node child = node.getFirstChild(); child!=null; child = child.getNextSibling()) {
47              Text text = findFirstText(child);
48              if (text!=null) return text;
49          }
50          return null;
51      }
52  
53      /**
54       * Gets the first text descendent node of an element.
55       * This recursively looks more than one level to search
56       * for text in font nodes, etc. Throws a DOMException
57       * if the Text object is not found.
58       *
59       * @param node The starting node for the search.
60       * @return The text node or null if not found.
61       * @throws DOMException if the Text object is not found
62       */
63      public static Text getFirstText(Node node) {
64          Text text = findFirstText(node);
65          if (text==null) {
66              String   msg = "No child text mode found for element";
67              String   id = getID(node);
68              throw new DOMException((short) -1, msg+(id!=null ? "; id=\""+id+"\"" : ""));
69          }
70          return text;
71      }
72  
73      /**
74       * Automatically set text in a Node. Basically looks for 
75       * the first child Text node; if it finds one, it sets the
76       * text, if not, it creates a new one with the appropriate
77       * text. Throws a DOMException if it's illegal to add a Text
78       * child to the particular node.
79       *
80       * @param node the starting node for the search.
81       * @param node the text to be added
82       * @return the updated node
83       * @throws DOMException if the Text object is not found
84       */
85  /*
86      public static Node setTextInNode(Node node, String text) {
87          Text textComp = DOMUtil.findFirstText((Element) node);
88          if (textComp==null) {
89              textComp = node.getOwnerDocument().createTextNode(text);
90              node.appendChild(textComp);
91          } else {
92              textComp.setData(""+text);
93          }
94          return node;
95      }
96  */
97  
98  
99      /**
100      * Automatically set text in a Node. Basically we find the first
101      * Text node beneath the current node and replace it with a
102      * CDATASection for the incoming text. All other Text nodes are
103      * removed. Throws a DOMException if it's illegal to add a Text
104      * child to the particular node.
105      *
106      * @param node the starting node for the search.
107      * @param text the text to be set
108      * @param allowMarkupInText whether to allow markup in text to pass through unparsed
109      * @return the updated node
110      * @throws DOMException if the Text object is not found
111      */
112     public static Node setTextInNode(Node node, String   text, boolean allowMarkupInText) {
113         //start by setting the value in the first text node we find with a comment
114         Comment comment = node.getOwnerDocument().createComment("");
115         Node newNode = null;
116         
117         //csc_092701.1 - support both encoded/unencoded text
118         if (allowMarkupInText) newNode = node.getOwnerDocument().createCDATASection(text);
119         else newNode = node.getOwnerDocument().createTextNode(text);
120 //System.out.println ("newNode: "+newNode);
121         
122         Text textComp = DOMUtil.findFirstText((Element) node);
123 //System.out.println ("textComp:"+textComp);        
124         if (textComp==null) {
125             node.appendChild(comment);
126         } else {
127             Node parent = textComp.getParentNode();
128             parent.replaceChild(comment, textComp);
129         }
130         
131         //now remove all the rest of the text nodes
132         removeAllTextNodes(node);        
133 
134         //now replace the comment with the newNode
135         Node parent = comment.getParentNode();
136         parent.replaceChild(newNode, comment);
137 //System.out.println ("parent:  "+parent);        
138 //System.out.println ("result:  "+DOMUtil.findFirstText((Element) parent));        
139 //DOMUtil.printStackTrace(parent.getOwnerDocument().getDocumentElement());
140         return node;
141     }
142     
143     /**
144      * Remove all text nodes below this node
145      *
146      * @param node The starting node for the search.
147      */
148     public static void removeAllTextNodes(Node node) {
149         if (node==null) return;
150         if (!node.hasChildNodes()) return;
151         NodeList nl = node.getChildNodes();
152         for (int i=nl.getLength()-1; i>=0; i--) {
153             Node n = (Node) nl.item(i);        
154             if (n instanceof Text) node.removeChild(n);
155             else removeAllTextNodes(n);
156         }
157     }
158     
159     /**
160      * Given a Node name, return the "id" attribute if it exists.
161      * If it does not exist, return null instead. This is basically
162      * just a convenience method to cast the node to element and 
163      * return the id from that.
164      *
165      * @param node the node name in question
166      * @return the id value for the given node, if it exists. null if 
167      *        doesn't
168      */
169     public static String   getID(Node node) {
170         return getID(node, null);
171     }
172 
173     /**
174      * Given a Node, return the "id" attribute if it exists.
175      * If it does not exist, return nullResponse instead. This is basically
176      * just a convenience method to cast the node to element and 
177      * return the id from that.
178      *
179      * @param node the node in question
180      * @param nullResponse the response to be returned if the id attribute
181      *        does not exist
182      * @return the id value for the given node, if it exists. null if 
183      *        doesn't
184      */
185     public static String   getID(Node node, String   nullResponse) {
186         String   nodeName = nullResponse;
187         if (node instanceof Element) {
188             nodeName = ((Element) node).getAttribute("id");
189         }
190         return nodeName;
191     }
192 
193     /**
194      * <p>utility method to recursively print the stack trace for a DOM Node</p>
195      */
196     public static void printStackTrace(Node node) {
197         printStackTrace(node, System.out, 0);
198     }
199 
200     /**
201      * <p>utility method to recursively print the stack trace for a DOM Node</p>
202      *
203      * <p>Bounds: <br>
204      * If depth < 0, the method returns immediately</p>
205      *
206      * @param node the node in question
207      * @param out OutputStream to print to
208      * @param depth inset depth at which to start printing
209      */
210     public static void printStackTrace(Node node, OutputStream out, int depth) {
211         if (depth<0) depth = 0;
212         if (depth>25) depth = 25;
213         String   spaces = "                                                                              ";
214         String   inset = spaces.substring(0,depth*3);
215         print (out, inset+node.getClass().getName()+"@"+Integer.toHexString(node.hashCode()));            
216         StringBuffer   sb = new StringBuffer  (200);
217         String   sep = "";
218         Iterator it = Classes.getAllInterfaces(node).iterator();
219         while (it.hasNext()) {
220             sb.append(sep+Classes.getShortClassName((Class  ) it.next()));
221             sep = ", ";
222         }
223         print (out, inset+"   implements: {"+sb.toString()+"}");
224         print (out, inset+"   name:"+node.getNodeName());
225         print (out, inset+"   attr:"+(node.hasAttributes() ? "" : " (n/a)"));
226         if (node.hasAttributes()) {
227             NamedNodeMap nnm = node.getAttributes();
228             for (int i=0,max=nnm.getLength(); i<max; i++) {
229                 Attr attr = (Attr) nnm.item(i);
230                 print (out, inset+"      "+attr.getName()+":"+attr.getValue());
231             }        
232             print (out, inset+"   /end attr");
233         }
234         print (out, inset+"   children:"+(node.hasChildNodes() ? "" : " (n/a)"));
235         if (node.hasChildNodes()) {
236             NodeList nl = node.getChildNodes();
237             for (int i=0,max=nl.getLength(); i<max; i++) {
238                 printStackTrace(nl.item(i), out, depth+2);
239             }        
240             print (out, inset+"   /end children");
241         }
242         print (out, inset+"/end @" + Integer.toHexString(node.hashCode()));
243         if (out!=null) try {out.flush();} catch (IOException ioe) {}
244     }
245     
246 
247     protected static void print(OutputStream out, String   s) {
248         if (out!=null) try {
249             out.write(s.getBytes());
250             out.write(sep);
251         } catch (IOException ioe) {}
252     }
253 
254     public static void printMarkup(Node node) {
255         printMarkup(node, new PrintWriter(System.out, true), true, true, 0);
256     }
257 
258     public static void printMarkup(Node node, PrintWriter out, boolean isHtml, boolean skipComments, int depth) {
259         if (depth<0) depth = 0;
260         if (depth>35) depth = 35;
261         String   spaces = "                                                                              ";
262         String   inset = spaces.substring(0,depth*2);
263 
264         //element
265         if (node instanceof Element) {
266             Element el = (Element) node;
267             out.print(inset+"<"+el.getTagName());
268             String   sep = " ";
269             NamedNodeMap nnm = el.getAttributes();
270             for (int i=0, max=nnm.getLength(); i<max; i++) {
271                 Attr attr = (Attr) nnm.item(i);
272                 out.print(sep+attr.getName()+"=\""+attr.getValue()+"\"");
273             }
274             out.println(">"+" {@"+Integer.toHexString(node.hashCode())+"}");
275         
276             //print the children
277             printChildMarkup(node, out, isHtml, skipComments, depth);
278         
279             //print the closing tag (if it's not forbidden, as the given html tags are)
280             String   tag = el.getTagName().toLowerCase();
281             if (!isHtml || 
282                (!tag.equals("area") && !tag.equals("base") && !tag.equals("basefont") &&
283                 !tag.equals("br") && !tag.equals("col") && !tag.equals("frame") &&
284                 !tag.equals("hr") && !tag.equals("image") && !tag.equals("input") &&
285                 !tag.equals("isindex") && !tag.equals("link") && !tag.equals("meta") &&
286                 !tag.equals("param"))) {
287                 out.println(inset+"</"+el.getTagName()+">");
288             }
289         
290         //character data
291         } else if (node instanceof CharacterData) {
292             if (node instanceof Comment) {
293                 if (!skipComments) {
294                     out.println(inset+"<!-- "+((CharacterData) node).getData()+" -->");
295                 }
296             } else {
297                 out.println(inset+((CharacterData) node).getData());
298             }            
299 
300         //node with child nodes        
301         } else if (node.hasChildNodes()) {
302             printChildMarkup(node, out, isHtml, skipComments, depth);
303 
304         //anything else
305         } else {        
306             System.out.println("Unhandled element:"+node.getClass().getName());
307             org.enhydra.barracuda.plankton.data.CollectionsUtil.printStackTrace(Classes.getAllInterfaces(node));
308         }
309     }    
310     
311     protected static void printChildMarkup(Node node, PrintWriter out, boolean isHtml, boolean skipComments, int depth) {
312         Node child = node.getFirstChild();
313         if (child==null) return;
314         do {
315             printMarkup(child, out, isHtml, skipComments, depth+1);
316             child = child.getNextSibling();
317         } while (child!=null);
318     }
319 
320 
321 }
322
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