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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  package org.apache.commons.jxpath;
17  
18  import java.net.URL;
19  
20  import javax.xml.transform.Source;
21  import javax.xml.transform.Transformer;
22  import javax.xml.transform.TransformerFactory;
23  import javax.xml.transform.dom.DOMResult;
24  
25  import org.apache.commons.jxpath.xml.DocumentContainer;
26  import org.w3c.dom.Document;
27  
28  /***
29   * An XML document container reads and parses XML only when it is
30   * accessed.  JXPath traverses Containers transparently -
31   * you use the same paths to access objects in containers as you
32   * do to access those objects directly.  You can create
33   * XMLDocumentContainers for various XML documents that may or
34   * may not be accessed by XPaths.  If they are, they will be automatically
35   * read, parsed and traversed. If they are not - they won't be
36   * read at all.
37   *
38   * @deprecated 1.1 Please use org.apache.commons.jxpath.xml.DocumentContainer
39   *
40   * @author Dmitri Plotnikov
41   * @version $Revision: 1.11 $ $Date: 2004/02/29 14:17:42 $
42   */
43  public class XMLDocumentContainer implements Container {
44  
45      private DocumentContainer delegate;
46      private Object document;
47      private URL xmlURL;
48      private Source source;
49      private String parser;
50  
51      /***
52       * @param  URL is a URL for an XML file. Use getClass().getResource
53       * (resourceName) to load XML from a resource file.
54       */
55      public XMLDocumentContainer(URL xmlURL) {
56          delegate = new DocumentContainer(xmlURL);
57      }
58  
59      public XMLDocumentContainer(Source source) {
60          this.source = source;
61          if (source == null) {
62              throw new RuntimeException("Source is null");
63          }
64      }
65  
66      /***
67       * Reads XML, caches it internally and returns the Document.
68       */
69      public Object getValue() {
70          if (document == null) {
71              try {
72                  if (source != null) {
73                      DOMResult result = new DOMResult();
74                      Transformer trans =
75                          TransformerFactory.newInstance().newTransformer();
76                      trans.transform(source, result);
77                      document = (Document) result.getNode();
78                  }
79                  else {
80                      document = delegate.getValue();
81                  }
82              }
83              catch (Exception ex) {
84                  throw new JXPathException(
85                      "Cannot read XML from: "
86                          + (xmlURL != null
87                              ? xmlURL.toString()
88                              : (source != null
89                                  ? source.getSystemId()
90                                  : "<<undefined source>>")),
91                      ex);
92              }
93          }
94          return document;
95      }
96  
97      /***
98       * Throws an UnsupportedOperationException
99       */
100     public void setValue(Object value) {
101         throw new UnsupportedOperationException();
102     }
103 }