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1 /*
2  * Licensed to the Apache Software Foundation (ASF) under one
3  * or more contributor license agreements. See the NOTICE file
4  * distributed with this work for additional information
5  * regarding copyright ownership. The ASF licenses this file
6  * to you under the Apache License, Version 2.0 (the  "License");
7  * you may not use this file except in compliance with the License.
8  * You may obtain a copy of the License at
9  *
10  *     http://www.apache.org/licenses/LICENSE-2.0
11  *
12  * Unless required by applicable law or agreed to in writing, software
13  * distributed under the License is distributed on an "AS IS" BASIS,
14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15  * See the License for the specific language governing permissions and
16  * limitations under the License.
17  */
18 /*
19  * $Id: SourceTreeManager.java 468655 2006-10-28 07:12:06Z minchau $
20  */
21 package org.apache.xpath;
22 
23 import java.io.IOException;
24 import java.util.Vector;
25 
26 import javax.xml.transform.Source;
27 import javax.xml.transform.SourceLocator;
28 import javax.xml.transform.TransformerException;
29 import javax.xml.transform.URIResolver;
30 import javax.xml.transform.sax.SAXSource;
31 import javax.xml.transform.stream.StreamSource;
32 
33 import org.apache.xml.dtm.DTM;
34 import org.apache.xml.utils.SystemIDResolver;
35 
36 import org.xml.sax.XMLReader;
37 import org.xml.sax.helpers.XMLReaderFactory;
38 
39 /**
40  * This class bottlenecks all management of source trees.  The methods
41  * in this class should allow easy garbage collection of source
42  * trees (not yet!), and should centralize parsing for those source trees.
43  */
44 public class SourceTreeManager
45 {
46 
47   /** Vector of SourceTree objects that this manager manages. */
48   private Vector m_sourceTree = new Vector();
49 
50   /**
51    * Reset the list of SourceTree objects that this manager manages.
52    *
53    */
reset()54   public void reset()
55   {
56     m_sourceTree = new Vector();
57   }
58 
59   /** The TrAX URI resolver used to obtain source trees. */
60   URIResolver m_uriResolver;
61 
62   /**
63    * Set an object that will be used to resolve URIs used in
64    * document(), etc.
65    * @param resolver An object that implements the URIResolver interface,
66    * or null.
67    */
setURIResolver(URIResolver resolver)68   public void setURIResolver(URIResolver resolver)
69   {
70     m_uriResolver = resolver;
71   }
72 
73   /**
74    * Get the object that will be used to resolve URIs used in
75    * document(), etc.
76    * @return An object that implements the URIResolver interface,
77    * or null.
78    */
getURIResolver()79   public URIResolver getURIResolver()
80   {
81     return m_uriResolver;
82   }
83 
84   /**
85    * Given a document, find the URL associated with that document.
86    * @param owner Document that was previously processed by this liaison.
87    *
88    * @return The base URI of the owner argument.
89    */
findURIFromDoc(int owner)90   public String findURIFromDoc(int owner)
91   {
92     int n = m_sourceTree.size();
93 
94     for (int i = 0; i < n; i++)
95     {
96       SourceTree sTree = (SourceTree) m_sourceTree.elementAt(i);
97 
98       if (owner == sTree.m_root)
99         return sTree.m_url;
100     }
101 
102     return null;
103   }
104 
105   /**
106    * This will be called by the processor when it encounters
107    * an xsl:include, xsl:import, or document() function.
108    *
109    * @param base The base URI that should be used.
110    * @param urlString Value from an xsl:import or xsl:include's href attribute,
111    * or a URI specified in the document() function.
112    *
113    * @return a Source that can be used to process the resource.
114    *
115    * @throws IOException
116    * @throws TransformerException
117    */
resolveURI( String base, String urlString, SourceLocator locator)118   public Source resolveURI(
119           String base, String urlString, SourceLocator locator)
120             throws TransformerException, IOException
121   {
122 
123     Source source = null;
124 
125     if (null != m_uriResolver)
126     {
127       source = m_uriResolver.resolve(urlString, base);
128     }
129 
130     if (null == source)
131     {
132       String uri = SystemIDResolver.getAbsoluteURI(urlString, base);
133 
134       source = new StreamSource(uri);
135     }
136 
137     return source;
138   }
139 
140   /** JJK: Support  <?xalan:doc_cache_off?> kluge in ElemForEach.
141    * TODO: This function is highly dangerous. Cache management must be improved.
142    *
143    * @param n The node to remove.
144    */
removeDocumentFromCache(int n)145   public void removeDocumentFromCache(int n)
146   {
147     if(DTM.NULL ==n)
148       return;
149     for(int i=m_sourceTree.size()-1;i>=0;--i)
150     {
151       SourceTree st=(SourceTree)m_sourceTree.elementAt(i);
152       if(st!=null && st.m_root==n)
153       {
154 	m_sourceTree.removeElementAt(i);
155 	return;
156       }
157     }
158   }
159 
160 
161 
162   /**
163    * Put the source tree root node in the document cache.
164    * TODO: This function needs to be a LOT more sophisticated.
165    *
166    * @param n The node to cache.
167    * @param source The Source object to cache.
168    */
putDocumentInCache(int n, Source source)169   public void putDocumentInCache(int n, Source source)
170   {
171 
172     int cachedNode = getNode(source);
173 
174     if (DTM.NULL != cachedNode)
175     {
176       if (!(cachedNode == n))
177         throw new RuntimeException(
178           "Programmer's Error!  "
179           + "putDocumentInCache found reparse of doc: "
180           + source.getSystemId());
181       return;
182     }
183     if (null != source.getSystemId())
184     {
185       m_sourceTree.addElement(new SourceTree(n, source.getSystemId()));
186     }
187   }
188 
189   /**
190    * Given a Source object, find the node associated with it.
191    *
192    * @param source The Source object to act as the key.
193    *
194    * @return The node that is associated with the Source, or null if not found.
195    */
getNode(Source source)196   public int getNode(Source source)
197   {
198 
199 //    if (source instanceof DOMSource)
200 //      return ((DOMSource) source).getNode();
201 
202     // TODO: Not sure if the BaseID is really the same thing as the ID.
203     String url = source.getSystemId();
204 
205     if (null == url)
206       return DTM.NULL;
207 
208     int n = m_sourceTree.size();
209 
210     // System.out.println("getNode: "+n);
211     for (int i = 0; i < n; i++)
212     {
213       SourceTree sTree = (SourceTree) m_sourceTree.elementAt(i);
214 
215       // System.out.println("getNode -         url: "+url);
216       // System.out.println("getNode - sTree.m_url: "+sTree.m_url);
217       if (url.equals(sTree.m_url))
218         return sTree.m_root;
219     }
220 
221     // System.out.println("getNode - returning: "+node);
222     return DTM.NULL;
223   }
224 
225   /**
226    * Get the source tree from the a base URL and a URL string.
227    *
228    * @param base The base URI to use if the urlString is relative.
229    * @param urlString An absolute or relative URL string.
230    * @param locator The location of the caller, for diagnostic purposes.
231    *
232    * @return should be a non-null reference to the node identified by the
233    * base and urlString.
234    *
235    * @throws TransformerException If the URL can not resolve to a node.
236    */
getSourceTree( String base, String urlString, SourceLocator locator, XPathContext xctxt)237   public int getSourceTree(
238           String base, String urlString, SourceLocator locator, XPathContext xctxt)
239             throws TransformerException
240   {
241 
242     // System.out.println("getSourceTree");
243     try
244     {
245       Source source = this.resolveURI(base, urlString, locator);
246 
247       // System.out.println("getSourceTree - base: "+base+", urlString: "+urlString+", source: "+source.getSystemId());
248       return getSourceTree(source, locator, xctxt);
249     }
250     catch (IOException ioe)
251     {
252       throw new TransformerException(ioe.getMessage(), locator, ioe);
253     }
254 
255     /* catch (TransformerException te)
256      {
257        throw new TransformerException(te.getMessage(), locator, te);
258      }*/
259   }
260 
261   /**
262    * Get the source tree from the input source.
263    *
264    * @param source The Source object that should identify the desired node.
265    * @param locator The location of the caller, for diagnostic purposes.
266    *
267    * @return non-null reference to a node.
268    *
269    * @throws TransformerException if the Source argument can't be resolved to
270    *         a node.
271    */
getSourceTree(Source source, SourceLocator locator, XPathContext xctxt)272   public int getSourceTree(Source source, SourceLocator locator, XPathContext xctxt)
273           throws TransformerException
274   {
275 
276     int n = getNode(source);
277 
278     if (DTM.NULL != n)
279       return n;
280 
281     n = parseToNode(source, locator, xctxt);
282 
283     if (DTM.NULL != n)
284       putDocumentInCache(n, source);
285 
286     return n;
287   }
288 
289   /**
290    * Try to create a DOM source tree from the input source.
291    *
292    * @param source The Source object that identifies the source node.
293    * @param locator The location of the caller, for diagnostic purposes.
294    *
295    * @return non-null reference to node identified by the source argument.
296    *
297    * @throws TransformerException if the source argument can not be resolved
298    *         to a source node.
299    */
parseToNode(Source source, SourceLocator locator, XPathContext xctxt)300   public int parseToNode(Source source, SourceLocator locator, XPathContext xctxt)
301           throws TransformerException
302   {
303 
304     try
305     {
306       Object xowner = xctxt.getOwnerObject();
307       DTM dtm;
308       if(null != xowner && xowner instanceof org.apache.xml.dtm.DTMWSFilter)
309       {
310         dtm = xctxt.getDTM(source, false,
311                           (org.apache.xml.dtm.DTMWSFilter)xowner, false, true);
312       }
313       else
314       {
315         dtm = xctxt.getDTM(source, false, null, false, true);
316       }
317       return dtm.getDocument();
318     }
319     catch (Exception e)
320     {
321       //e.printStackTrace();
322       throw new TransformerException(e.getMessage(), locator, e);
323     }
324 
325   }
326 
327   /**
328    * This method returns the SAX2 parser to use with the InputSource
329    * obtained from this URI.
330    * It may return null if any SAX2-conformant XML parser can be used,
331    * or if getInputSource() will also return null. The parser must
332    * be free for use (i.e.
333    * not currently in use for another parse().
334    *
335    * @param inputSource The value returned from the URIResolver.
336    * @return a SAX2 XMLReader to use to resolve the inputSource argument.
337    * @param locator The location of the original caller, for diagnostic purposes.
338    *
339    * @throws TransformerException if the reader can not be created.
340    */
getXMLReader(Source inputSource, SourceLocator locator)341   public static XMLReader getXMLReader(Source inputSource, SourceLocator locator)
342           throws TransformerException
343   {
344 
345     try
346     {
347       XMLReader reader = (inputSource instanceof SAXSource)
348                          ? ((SAXSource) inputSource).getXMLReader() : null;
349 
350       if (null == reader)
351       {
352         try {
353           javax.xml.parsers.SAXParserFactory factory=
354               javax.xml.parsers.SAXParserFactory.newInstance();
355           factory.setNamespaceAware( true );
356           javax.xml.parsers.SAXParser jaxpParser=
357               factory.newSAXParser();
358           reader=jaxpParser.getXMLReader();
359 
360         } catch( javax.xml.parsers.ParserConfigurationException ex ) {
361           throw new org.xml.sax.SAXException( ex );
362         } catch( javax.xml.parsers.FactoryConfigurationError ex1 ) {
363             throw new org.xml.sax.SAXException( ex1.toString() );
364         } catch( NoSuchMethodError ex2 ) {
365         }
366         catch (AbstractMethodError ame){}
367         if(null == reader)
368           reader = XMLReaderFactory.createXMLReader();
369       }
370 
371       try
372       {
373         reader.setFeature("http://xml.org/sax/features/namespace-prefixes",
374                           true);
375       }
376       catch (org.xml.sax.SAXException se)
377       {
378 
379         // What can we do?
380         // TODO: User diagnostics.
381       }
382 
383       return reader;
384     }
385     catch (org.xml.sax.SAXException se)
386     {
387       throw new TransformerException(se.getMessage(), locator, se);
388     }
389   }
390 }
391