001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.commons.jxpath;
018
019 import java.net.URL;
020
021 import javax.xml.transform.Source;
022 import javax.xml.transform.Transformer;
023 import javax.xml.transform.TransformerFactory;
024 import javax.xml.transform.dom.DOMResult;
025
026 import org.apache.commons.jxpath.xml.DocumentContainer;
027 import org.w3c.dom.Document;
028
029 /**
030 * An XML document container reads and parses XML only when it is
031 * accessed. JXPath traverses Containers transparently -
032 * you use the same paths to access objects in containers as you
033 * do to access those objects directly. You can create
034 * XMLDocumentContainers for various XML documents that may or
035 * may not be accessed by XPaths. If they are, they will be automatically
036 * read, parsed and traversed. If they are not - they won't be
037 * read at all.
038 *
039 * @deprecated 1.1 Please use {@link DocumentContainer}
040 *
041 * @author Dmitri Plotnikov
042 * @version $Revision: 652845 $ $Date: 2008-05-02 12:46:46 -0500 (Fri, 02 May 2008) $
043 */
044 public class XMLDocumentContainer implements Container {
045
046 private DocumentContainer delegate;
047 private Object document;
048 private URL xmlURL;
049 private Source source;
050
051 /**
052 * Create a new XMLDocumentContainer.
053 * @param xmlURL a URL for an XML file. Use getClass().getResource(resourceName)
054 * to load XML from a resource file.
055 */
056 public XMLDocumentContainer(URL xmlURL) {
057 this.xmlURL = xmlURL;
058 delegate = new DocumentContainer(xmlURL);
059 }
060
061 /**
062 * Create a new XMLDocumentContainer.
063 * @param source XML source
064 */
065 public XMLDocumentContainer(Source source) {
066 this.source = source;
067 if (source == null) {
068 throw new RuntimeException("Source is null");
069 }
070 }
071
072 /**
073 * Reads XML, caches it internally and returns the Document.
074 * @return Object value
075 */
076 public Object getValue() {
077 if (document == null) {
078 try {
079 if (source != null) {
080 DOMResult result = new DOMResult();
081 Transformer trans =
082 TransformerFactory.newInstance().newTransformer();
083 trans.transform(source, result);
084 document = (Document) result.getNode();
085 }
086 else {
087 document = delegate.getValue();
088 }
089 }
090 catch (Exception ex) {
091 throw new JXPathException(
092 "Cannot read XML from: "
093 + (xmlURL != null
094 ? xmlURL.toString()
095 : (source != null
096 ? source.getSystemId()
097 : "<<undefined source>>")),
098 ex);
099 }
100 }
101 return document;
102 }
103
104 /**
105 * Throws an UnsupportedOperationException
106 * @param value to set
107 */
108 public void setValue(Object value) {
109 throw new UnsupportedOperationException();
110 }
111 }