StylesheetPIHandler


1   /*
2    * Copyright 1999-2004 The Apache Software Foundation.
3    *
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    *
8    *     http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  /*
17   * $Id: StylesheetPIHandler.java,v 1.2 2004/02/17 04:21:14 minchau Exp $
18   */
19  package org.apache.xml.utils;
20  
21  import java.util.StringTokenizer  ;
22  import java.util.Vector  ;
23  
24  import javax.xml.transform.Source  ;
25  import javax.xml.transform.TransformerException  ;
26  import javax.xml.transform.URIResolver  ;
27  import javax.xml.transform.sax.SAXSource  ;
28  
29  import org.apache.xml.utils.SystemIDResolver;
30  
31  import org.xml.sax.Attributes  ;
32  import org.xml.sax.InputSource  ;
33  import org.xml.sax.helpers.DefaultHandler  ;
34  
35  /**
36   * Search for the xml-stylesheet processing instructions in an XML document.
37   * @see <a HREF="http://www.w3.org/TR/xml-stylesheet/">Associating Style Sheets with XML documents, Version 1.0</a>
38   */
39  public class StylesheetPIHandler extends DefaultHandler  
40  {
41    /** The baseID of the document being processed.  */
42    String   m_baseID;
43  
44    /** The desired media criteria. */
45    String   m_media;
46  
47    /** The desired title criteria.  */
48    String   m_title;
49  
50    /** The desired character set criteria.   */
51    String   m_charset;
52  
53    /** A list of SAXSource objects that match the criteria.  */
54    Vector   m_stylesheets = new Vector  ();
55    
56    // Add code to use a URIResolver. Patch from Dmitri Ilyin. 
57    
58    /**
59     * The object that implements the URIResolver interface,
60     * or null.
61     */
62    URIResolver   m_uriResolver;
63  
64    /**
65     * Get the object that will be used to resolve URIs in href 
66     * in xml-stylesheet processing instruction.
67     *
68     * @param resolver An object that implements the URIResolver interface,
69     * or null.
70     */
71    public void setURIResolver(URIResolver   resolver)
72    {
73      m_uriResolver = resolver;
74    }
75  
76    /**
77     * Get the object that will be used to resolve URIs in href 
78     * in xml-stylesheet processing instruction.
79     *
80     * @return The URIResolver that was set with setURIResolver.
81     */
82    public URIResolver   getURIResolver()
83    {
84      return m_uriResolver;
85    }
86  
87    /**
88     * Construct a StylesheetPIHandler instance that will search 
89     * for xml-stylesheet PIs based on the given criteria.
90     *
91     * @param baseID The base ID of the XML document, needed to resolve 
92     *               relative IDs.
93     * @param media The desired media criteria.
94     * @param title The desired title criteria.
95     * @param charset The desired character set criteria.
96     */
97    public StylesheetPIHandler(String   baseID, String   media, String   title,
98                               String   charset)
99    {
100 
101     m_baseID = baseID;
102     m_media = media;
103     m_title = title;
104     m_charset = charset;
105   }
106 
107   /**
108    * Return the last stylesheet found that match the constraints.
109    *
110    * @return Source object that references the last stylesheet reference 
111    *         that matches the constraints.
112    */
113   public Source   getAssociatedStylesheet()
114   {
115 
116     int sz = m_stylesheets.size();
117 
118     if (sz > 0)
119     {
120       Source   source = (Source  ) m_stylesheets.elementAt(sz-1);
121       return source;      
122     }
123     else
124       return null;
125   }
126 
127   /**
128    * Handle the xml-stylesheet processing instruction.
129    *
130    * @param target The processing instruction target.
131    * @param data The processing instruction data, or null if
132    *             none is supplied.
133    * @throws org.xml.sax.SAXException Any SAX exception, possibly
134    *            wrapping another exception.
135    * @see org.xml.sax.ContentHandler#processingInstruction
136    * @see <a HREF="http://www.w3.org/TR/xml-stylesheet/">Associating Style Sheets with XML documents, Version 1.0</a>
137    */
138   public void processingInstruction(String   target, String   data)
139           throws org.xml.sax.SAXException  
140   {
141 
142     if (target.equals("xml-stylesheet"))
143     {
144       String   href = null;  // CDATA #REQUIRED
145       String   type = null;  // CDATA #REQUIRED
146       String   title = null;  // CDATA #IMPLIED
147       String   media = null;  // CDATA #IMPLIED
148       String   charset = null;  // CDATA #IMPLIED
149       boolean alternate = false;  // (yes|no) "no"
150       StringTokenizer   tokenizer = new StringTokenizer  (data, " \t=\n", true);
151       boolean lookedAhead = false; 
152       Source   source = null;
153 
154       String   token = "";
155       while (tokenizer.hasMoreTokens())
156       {        
157         if (!lookedAhead)
158           token = tokenizer.nextToken();
159         else
160           lookedAhead = false;
161         if (tokenizer.hasMoreTokens() && 
162                (token.equals(" ") || token.equals("\t") || token.equals("=")))
163           continue;
164           
165         String   name = token;  
166         if (name.equals("type"))
167         { 
168           token = tokenizer.nextToken();
169           while (tokenizer.hasMoreTokens() && 
170                (token.equals(" " ) || token.equals("\t") || token.equals("=")))
171             token = tokenizer.nextToken();
172           type = token.substring(1, token.length() - 1);
173           
174         }
175         else if (name.equals("href"))
176         {
177           token = tokenizer.nextToken();
178           while (tokenizer.hasMoreTokens() && 
179                (token.equals(" " ) || token.equals("\t") || token.equals("=")))
180             token = tokenizer.nextToken();
181           href = token;
182           if (tokenizer.hasMoreTokens())
183           {
184             token = tokenizer.nextToken();
185             // If the href value has parameters to be passed to a 
186             // servlet(something like "foobar?id=12..."), 
187             // we want to make sure we get them added to
188             // the href value. Without this check, we would move on 
189             // to try to process another attribute and that would be
190             // wrong.
191             // We need to set lookedAhead here to flag that we
192             // already have the next token. 
193             while ( token.equals("=") && tokenizer.hasMoreTokens())
194             {  
195               href = href + token + tokenizer.nextToken();
196               if (tokenizer.hasMoreTokens())
197               {  
198                 token = tokenizer.nextToken();
199                 lookedAhead = true;
200               }
201               else
202               {
203                 break;
204               }
205             }
206           }
207           href = href.substring(1, href.length() - 1);
208           try
209           { 
210             // Add code to use a URIResolver. Patch from Dmitri Ilyin. 
211             if (m_uriResolver != null) 
212             {
213               source = m_uriResolver.resolve(href, m_baseID);
214             } 
215            else 
216             {
217               href = SystemIDResolver.getAbsoluteURI(href, m_baseID);
218               source = new SAXSource  (new InputSource  (href));
219             }            
220           }
221           catch(TransformerException   te)
222           {
223             throw new org.xml.sax.SAXException  (te);
224           }
225         }
226         else if (name.equals("title"))
227         {
228           token = tokenizer.nextToken();
229           while (tokenizer.hasMoreTokens() && 
230                (token.equals(" " ) || token.equals("\t") || token.equals("=")))
231             token = tokenizer.nextToken();
232           title = token.substring(1, token.length() - 1);
233         }
234         else if (name.equals("media"))
235         {
236           token = tokenizer.nextToken();
237           while (tokenizer.hasMoreTokens() && 
238                (token.equals(" " ) || token.equals("\t") || token.equals("=")))
239             token = tokenizer.nextToken();
240           media = token.substring(1, token.length() - 1);
241         }
242         else if (name.equals("charset"))
243         {
244           token = tokenizer.nextToken();
245           while (tokenizer.hasMoreTokens() && 
246               (token.equals(" " ) || token.equals("\t") || token.equals("=")))
247             token = tokenizer.nextToken();
248           charset = token.substring(1, token.length() - 1);
249         }
250         else if (name.equals("alternate"))
251         {
252           token = tokenizer.nextToken();
253           while (tokenizer.hasMoreTokens() && 
254                (token.equals(" " ) || token.equals("\t") || token.equals("=")))
255             token = tokenizer.nextToken();
256           alternate = token.substring(1, token.length()
257                                              - 1).equals("yes");
258         }
259         
260       }
261 
262       if ((null != type) 
263           && (type.equals("text/xsl") || type.equals("text/xml") || type.equals("application/xml+xslt"))  
264           && (null != href))
265       {
266         if (null != m_media)
267         {
268           if (null != media)
269           {
270             if (!media.equals(m_media))
271               return;
272           }
273           else
274             return;
275         }
276 
277         if (null != m_charset)
278         {
279           if (null != charset)
280           {
281             if (!charset.equals(m_charset))
282               return;
283           }
284           else
285             return;
286         }
287 
288         if (null != m_title)
289         {
290           if (null != title)
291           {
292             if (!title.equals(m_title))
293               return;
294           }
295           else
296             return;
297         }
298 
299         m_stylesheets.addElement(source);
300       }
301     }
302   }
303   
304   
305   /**
306    * The spec notes that "The xml-stylesheet processing instruction is allowed only in the prolog of an XML document.",
307    * so, at least for right now, I'm going to go ahead an throw a TransformerException
308    * in order to stop the parse.
309    *
310    * @param uri The Namespace URI, or an empty string.
311    * @param localName The local name (without prefix), or empty string if not namespace processing.
312    * @param rawName The qualified name (with prefix).
313    * @param attributes The specified or defaulted attributes.
314    *
315    * @throws StopParseException since there can be no valid xml-stylesheet processing 
316    *                            instructions past the first element.
317    */
318   public void startElement(
319           String   namespaceURI, String   localName, String   qName, Attributes   atts)
320             throws org.xml.sax.SAXException  
321   {
322     throw new StopParseException();
323   }
324 
325   /**
326     * Added additional getter and setter methods for the Base Id
327     * to fix bugzilla bug 24187
328     * 
329     */
330    public void setBaseId(String   baseId) {
331        m_baseID = baseId;
332  
333    }
334    public String    getBaseId() {
335        return m_baseID ;
336    }
337 
338 }
339
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