View Javadoc

1   package org.jaxen.dom4j;
2   
3   /*
4    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/dom4j/DocumentNavigator.java,v 1.28 2005/04/03 00:05:09 elharo Exp $
5    * $Revision: 1.28 $
6    * $Date: 2005/04/03 00:05:09 $
7    *
8    * ====================================================================
9    *
10   * Copyright (C) 2000-2005 bob mcwhirter & James Strachan.
11   * All rights reserved.
12   *
13   * Redistribution and use in source and binary forms, with or without
14   * modification, are permitted provided that the following conditions
15   * are met:
16   *
17   * 1. Redistributions of source code must retain the above copyright
18   *    notice, this list of conditions, and the following disclaimer.
19   *
20   * 2. Redistributions in binary form must reproduce the above copyright
21   *    notice, this list of conditions, and the disclaimer that follows
22   *    these conditions in the documentation and/or other materials
23   *    provided with the distribution.
24   *
25   * 3. The name "Jaxen" must not be used to endorse or promote products
26   *    derived from this software without prior written permission.  For
27   *    written permission, please contact license@jaxen.org.
28   *
29   * 4. Products derived from this software may not be called "Jaxen", nor
30   *    may "Jaxen" appear in their name, without prior written permission
31   *    from the Jaxen Project Management (pm@jaxen.org).
32   *
33   * In addition, we request (but do not require) that you include in the
34   * end-user documentation provided with the redistribution and/or in the
35   * software itself an acknowledgement equivalent to the following:
36   *     "This product includes software developed by the
37   *      Jaxen Project (http://www.jaxen.org/)."
38   * Alternatively, the acknowledgment may be graphical using the logos
39   * available at http://www.jaxen.org/
40   *
41   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
42   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
43   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
44   * DISCLAIMED.  IN NO EVENT SHALL THE Jaxen AUTHORS OR THE PROJECT
45   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
46   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
47   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
48   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
49   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
50   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
51   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
52   * SUCH DAMAGE.
53   *
54   * ====================================================================
55   * This software consists of voluntary contributions made by many
56   * individuals on behalf of the Jaxen Project and was originally
57   * created by bob mcwhirter <bob@werken.com> and
58   * James Strachan <jstrachan@apache.org>.  For more information on the
59   * Jaxen Project, please see <http://www.jaxen.org/>.
60   *
61   * $Id: DocumentNavigator.java,v 1.28 2005/04/03 00:05:09 elharo Exp $
62  */
63  
64  import java.util.ArrayList;
65  import java.util.HashSet;
66  import java.util.Iterator;
67  import java.util.List;
68  
69  import org.dom4j.Attribute;
70  import org.dom4j.Branch;
71  import org.dom4j.CDATA;
72  import org.dom4j.Comment;
73  import org.dom4j.Document;
74  import org.dom4j.DocumentException;
75  import org.dom4j.Element;
76  import org.dom4j.Namespace;
77  import org.dom4j.Node;
78  import org.dom4j.ProcessingInstruction;
79  import org.dom4j.QName;
80  import org.dom4j.Text;
81  import org.dom4j.io.SAXReader;
82  import org.jaxen.DefaultNavigator;
83  import org.jaxen.FunctionCallException;
84  import org.jaxen.NamedAccessNavigator;
85  import org.jaxen.Navigator;
86  import org.jaxen.XPath;
87  import org.jaxen.JaxenConstants;
88  import org.jaxen.saxpath.SAXPathException;
89  import org.jaxen.util.SingleObjectIterator;
90  
91  /*** 
92   * Interface for navigating around the DOM4J object model.
93   *
94   * <p>
95   * This class is not intended for direct usage, but is
96   * used by the Jaxen engine during evaluation.
97   * </p>
98   *
99   * @see XPath
100  *
101  * @author <a href="mailto:bob@werken.com">bob mcwhirter</a>
102  * @author Stephen Colebourne
103  */
104 public class DocumentNavigator extends DefaultNavigator implements NamedAccessNavigator
105 {
106     
107     private transient SAXReader reader;
108 
109     /*** Singleton implementation.
110      */
111     private static class Singleton
112     {
113         /*** Singleton instance.
114          */
115         private static DocumentNavigator instance = new DocumentNavigator();
116     }
117 
118     /*** Retrieve the singleton instance of this <code>DocumentNavigator</code>.
119      */
120     public static Navigator getInstance()
121     {
122         return Singleton.instance;
123     }
124 
125     public boolean isElement(Object obj)
126     {
127         return obj instanceof Element;
128     }
129 
130     public boolean isComment(Object obj)
131     {
132         return obj instanceof Comment;
133     }
134 
135     public boolean isText(Object obj)
136     {
137         return ( obj instanceof Text 
138                  ||
139                  obj instanceof CDATA );
140     }
141 
142     public boolean isAttribute(Object obj)
143     {
144         return obj instanceof Attribute;
145     }
146 
147     public boolean isProcessingInstruction(Object obj)
148     {
149         return obj instanceof ProcessingInstruction;
150     }
151 
152     public boolean isDocument(Object obj)
153     {
154         return obj instanceof Document;
155     }
156 
157     public boolean isNamespace(Object obj)
158     {
159         return obj instanceof Namespace;
160     }
161 
162     public String getElementName(Object obj)
163     {
164         Element elem = (Element) obj;
165 
166         return elem.getName();
167     }
168 
169     public String getElementNamespaceUri(Object obj)
170     {
171         Element elem = (Element) obj;
172         
173         String uri = elem.getNamespaceURI();
174         if ( uri == null)
175             return "";
176         else
177             return uri;
178     }
179 
180     public String getElementQName(Object obj)
181     {
182         Element elem = (Element) obj;
183 
184         return elem.getQualifiedName();
185     }
186 
187     public String getAttributeName(Object obj)
188     {
189         Attribute attr = (Attribute) obj;
190 
191         return attr.getName();
192     }
193 
194     public String getAttributeNamespaceUri(Object obj)
195     {
196         Attribute attr = (Attribute) obj;
197 
198         String uri = attr.getNamespaceURI();
199         if ( uri == null)
200             return "";
201         else
202             return uri;
203     }
204 
205     public String getAttributeQName(Object obj)
206     {
207         Attribute attr = (Attribute) obj;
208 
209         return attr.getQualifiedName();
210     }
211 
212     public Iterator getChildAxisIterator(Object contextNode)
213     {
214         Iterator result = null;
215         if ( contextNode instanceof Branch )
216         {
217             Branch node = (Branch) contextNode;
218             result = node.nodeIterator();
219         }
220         if (result != null) {
221             return result;
222         }
223         return JaxenConstants.EMPTY_ITERATOR;
224     }
225 
226     /***
227      * Retrieves an <code>Iterator</code> over the child elements that
228      * match the supplied name.
229      *
230      * @param contextNode  the origin context node
231      * @param localName  the local name of the children to return, always present
232      * @param namespacePrefix  the prefix of the namespace of the children to return
233      * @param namespaceURI  the uri of the namespace of the children to return
234      * @return an Iterator that traverses the named children, or null if none
235      */
236     public Iterator getChildAxisIterator(
237             Object contextNode, String localName, String namespacePrefix, String namespaceURI) {
238 
239         if ( contextNode instanceof Element ) {
240             Element node = (Element) contextNode;
241             return node.elementIterator(QName.get(localName, namespacePrefix, namespaceURI));
242         }
243         if ( contextNode instanceof Document ) {
244             Document node = (Document) contextNode;
245             Element el = node.getRootElement();
246             if (el.getName().equals(localName) == false) {
247                 return JaxenConstants.EMPTY_ITERATOR;
248             }
249             if (namespaceURI != null) {
250                 if (namespaceURI.equals(el.getNamespaceURI()) == false) {
251                     return JaxenConstants.EMPTY_ITERATOR;
252                 }
253             }
254             return new SingleObjectIterator(el);
255         }
256 
257         return JaxenConstants.EMPTY_ITERATOR;
258     }
259 
260     public Iterator getParentAxisIterator(Object contextNode)
261     {
262         if ( contextNode instanceof Document )
263         {
264             return JaxenConstants.EMPTY_ITERATOR;
265         }
266 
267         Node node = (Node) contextNode;
268 
269         Object parent = node.getParent();
270 
271         if ( parent == null )
272         {
273             parent = node.getDocument();
274         }
275         
276         return new SingleObjectIterator( parent );
277     }
278 
279     public Iterator getAttributeAxisIterator(Object contextNode)
280     {
281         if ( ! ( contextNode instanceof Element ) )
282         {
283             return JaxenConstants.EMPTY_ITERATOR;
284         }
285 
286         Element elem = (Element) contextNode;
287 
288         return elem.attributeIterator();
289     }
290 
291     /***
292      * Retrieves an <code>Iterator</code> over the attribute elements that
293      * match the supplied name.
294      *
295      * @param contextNode  the origin context node
296      * @param localName  the local name of the attributes to return, always present
297      * @param namespacePrefix  the prefix of the namespace of the attributes to return
298      * @param namespaceURI  the URI of the namespace of the attributes to return
299      * @return an Iterator that traverses the named attributes, not null
300      */
301     public Iterator getAttributeAxisIterator(
302             Object contextNode, String localName, String namespacePrefix, String namespaceURI) {
303 
304         if ( contextNode instanceof Element ) {
305             Element node = (Element) contextNode;
306             Attribute attr = node.attribute(QName.get(localName, namespacePrefix, namespaceURI));
307             if (attr == null) {
308                 return JaxenConstants.EMPTY_ITERATOR;
309             }
310             return new SingleObjectIterator(attr);
311         }
312         return JaxenConstants.EMPTY_ITERATOR;
313     }
314         
315     public Iterator getNamespaceAxisIterator(Object contextNode)
316     {
317         if ( ! ( contextNode instanceof Element ) )
318         {
319             return JaxenConstants.EMPTY_ITERATOR;
320         }
321 
322         Element element = (Element) contextNode;
323         List nsList = new ArrayList();
324         HashSet prefixes = new HashSet();
325         for ( Element context = element; context != null; context = context.getParent() ) {
326             List declaredNS = context.declaredNamespaces();
327             declaredNS.add(context.getNamespace());
328 
329             for ( Iterator iter = context.attributes().iterator(); iter.hasNext(); )
330             {
331                 Attribute attr = (Attribute) iter.next();
332                 declaredNS.add(attr.getNamespace());
333             }
334 
335             for ( Iterator iter = declaredNS.iterator(); iter.hasNext(); )
336             {
337                 Namespace namespace = (Namespace) iter.next();
338                 if (namespace != Namespace.NO_NAMESPACE)
339                 {
340                     String prefix = namespace.getPrefix();
341                     if ( ! prefixes.contains( prefix ) ) {
342                         prefixes.add( prefix );
343                         nsList.add( namespace.asXPathResult( element ) );
344                     }
345                 }
346             }
347         }
348         nsList.add( Namespace.XML_NAMESPACE.asXPathResult( element ) );
349         return nsList.iterator();
350     }
351 
352     public Object getDocumentNode(Object contextNode)
353     {
354         if ( contextNode instanceof Document ) 
355         {
356             return contextNode;
357         }
358         else if ( contextNode instanceof Node ) 
359         {
360             Node node = (Node) contextNode;
361             return node.getDocument();
362         }
363         return null;
364     }
365 
366     /*** Returns a parsed form of the given xpath string, which will be suitable
367      *  for queries on DOM4J documents.
368      */
369     public XPath parseXPath (String xpath) throws SAXPathException
370     {
371         return new Dom4jXPath(xpath);
372     }
373 
374     public Object getParentNode(Object contextNode)
375     {
376         if ( contextNode instanceof Node ) 
377         {
378             Node node = (Node) contextNode;
379             Object answer = node.getParent();
380             if ( answer == null ) 
381             {
382                 answer = node.getDocument();
383                 if (answer == contextNode) {
384                     return null;
385                 }
386             }
387             return answer;            
388         }
389         return null;
390     }
391 
392     public String getTextStringValue(Object obj)
393     {
394         return getNodeStringValue( (Node) obj );
395     }
396 
397     public String getElementStringValue(Object obj)
398     {
399         return getNodeStringValue( (Node) obj );
400     }
401 
402     public String getAttributeStringValue(Object obj)
403     {
404         return getNodeStringValue( (Node) obj );
405     }
406 
407     private String getNodeStringValue(Node node)
408     {
409         return node.getStringValue();
410     }
411 
412     public String getNamespaceStringValue(Object obj)
413     {
414         Namespace ns = (Namespace) obj;
415 
416         return ns.getURI();
417     }
418 
419     public String getNamespacePrefix(Object obj)
420     {
421         Namespace ns = (Namespace) obj;
422 
423         return ns.getPrefix();
424     }
425 
426     public String getCommentStringValue(Object obj)
427     {
428         Comment cmt = (Comment) obj;
429 
430         return cmt.getText();
431     }
432     
433     public String translateNamespacePrefixToUri(String prefix, Object context)
434     {
435         Element element = null;
436         if ( context instanceof Element ) 
437         {
438             element = (Element) context;
439         }
440         else if ( context instanceof Node )
441         {
442             Node node = (Node) context;
443             element = node.getParent();
444         }
445         if ( element != null )
446         {
447             Namespace namespace = element.getNamespaceForPrefix( prefix );
448 
449             if ( namespace != null ) 
450             {
451                 return namespace.getURI();
452             }
453         }
454         return null;
455     }
456     
457     public short getNodeType(Object node) 
458     {
459         if ( node instanceof Node )
460         {
461             return ((Node) node).getNodeType();
462         }
463         return 0;
464     }
465     
466     public Object getDocument(String uri) throws FunctionCallException
467     {
468         try
469         {
470             return getSAXReader().read( uri );
471         }
472         catch (DocumentException e)
473         {
474             throw new FunctionCallException("Failed to parse document for URI: " + uri, e);
475         }
476     }
477 
478     public String getProcessingInstructionTarget(Object obj)
479     {
480         ProcessingInstruction pi = (ProcessingInstruction) obj;
481 
482         return pi.getTarget();
483     }
484 
485     public String getProcessingInstructionData(Object obj)
486     {
487         ProcessingInstruction pi = (ProcessingInstruction) obj;
488 
489         return pi.getText();
490     }
491     
492     // Properties
493     //-------------------------------------------------------------------------    
494     public SAXReader getSAXReader()
495     {
496         if ( reader == null ) 
497         {
498             reader = new SAXReader();
499             reader.setMergeAdjacentText( true );
500         }
501         return reader;
502     }
503     
504     public void setSAXReader(SAXReader reader)
505     {
506         this.reader = reader;
507     }
508     
509 }