CmsXmlContentFactory


1   /*
2    * File   : $Source: /usr/local/cvs/opencms/src/org/opencms/xml/content/CmsXmlContentFactory.java,v $
3    * Date   : $Date: 2005/06/23 11:11:54 $
4    * Version: $Revision: 1.11 $
5    *
6    * This library is part of OpenCms -
7    * the Open Source Content Mananagement System
8    *
9    * Copyright (c) 2005 Alkacon Software GmbH (http://www.alkacon.com)
10   *
11   * This library is free software; you can redistribute it and/or
12   * modify it under the terms of the GNU Lesser General Public
13   * License as published by the Free Software Foundation; either
14   * version 2.1 of the License, or (at your option) any later version.
15   *
16   * This library is distributed in the hope that it will be useful,
17   * but WITHOUT ANY WARRANTY; without even the implied warranty of
18   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19   * Lesser General Public License for more details.
20   *
21   * For further information about Alkacon Software GmbH, please see the
22   * company website: http://www.alkacon.com
23   *
24   * For further information about OpenCms, please see the
25   * project website: http://www.opencms.org
26   * 
27   * You should have received a copy of the GNU Lesser General Public
28   * License along with this library; if not, write to the Free Software
29   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
30   */
31  
32  package org.opencms.xml.content;
33  
34  import org.opencms.file.CmsFile;
35  import org.opencms.file.CmsObject;
36  import org.opencms.file.CmsPropertyDefinition;
37  import org.opencms.file.CmsResource;
38  import org.opencms.i18n.CmsEncoder;
39  import org.opencms.loader.CmsLoaderException;
40  import org.opencms.loader.CmsXmlContentLoader;
41  import org.opencms.main.CmsException;
42  import org.opencms.main.OpenCms;
43  import org.opencms.xml.CmsXmlContentDefinition;
44  import org.opencms.xml.CmsXmlEntityResolver;
45  import org.opencms.xml.CmsXmlException;
46  import org.opencms.xml.CmsXmlUtils;
47  
48  import java.io.UnsupportedEncodingException  ;
49  import java.util.Locale  ;
50  
51  import javax.servlet.ServletRequest  ;
52  
53  import org.dom4j.Document;
54  import org.dom4j.DocumentHelper;
55  import org.xml.sax.EntityResolver  ;
56  
57  /**
58   * Provides factory methods to unmarshal (read) an XML content object.<p> 
59   *
60   * @author Alexander Kandzior 
61   * 
62   * @version $Revision: 1.11 $ 
63   * 
64   * @since 6.0.0 
65   */
66  public final class CmsXmlContentFactory {
67  
68      /**
69       * No instances of this class should be created.<p> 
70       */
71      private CmsXmlContentFactory() {
72  
73          // noop
74      }
75  
76      /**
77       * Create a new instance of an XML content based on the given content definiton,
78       * that will have one language node for the given locale all initialized with default values.<p> 
79       * 
80       * The given encoding is used when marshalling the XML again later.<p>
81       * 
82       * @param cms the current users OpenCms content
83       * @param locale the locale to generate the default content for
84       * @param encoding the encoding to use when marshalling the XML content later
85       * @param contentDefinition the content definiton to create the content for
86       * 
87       * @return the created XML content
88       */
89      public static CmsXmlContent createDocument(
90          CmsObject cms,
91          Locale   locale,
92          String   encoding,
93          CmsXmlContentDefinition contentDefinition) {
94  
95          // create the XML content
96          return new CmsXmlContent(cms, locale, encoding, contentDefinition);
97      }
98  
99      /**
100      * Factory method to unmarshal (generate) a XML content instance from a byte array
101      * that contains XML data.<p>
102      * 
103      * When unmarshalling, the encoding is read directly from the XML header of the byte array. 
104      * The given encoding is used only when marshalling the XML again later.<p>
105      * 
106      * @param xmlData the XML data in a byte array
107      * @param encoding the encoding to use when marshalling the XML content later
108      * @param resolver the XML entitiy resolver to use
109      * @return a XML content instance unmarshalled from the byte array
110      * @throws CmsXmlException if something goes wrong
111      */
112     public static CmsXmlContent unmarshal(byte[] xmlData, String   encoding, EntityResolver resolver)
113     throws CmsXmlException {
114 
115         return unmarshal(CmsXmlUtils.unmarshalHelper(xmlData, resolver), encoding, resolver);
116     }
117 
118     /**
119      * Factory method to unmarshal (read) a XML content instance from a OpenCms VFS file
120      * that contains XML data.<p>
121      * 
122      * @param cms the current cms object
123      * @param file the file with the XML data to unmarshal
124      * @return a XML page instance unmarshalled from the provided file
125      * @throws CmsXmlException if something goes wrong
126      */
127     public static CmsXmlContent unmarshal(CmsObject cms, CmsFile file) throws CmsXmlException {
128 
129         return unmarshal(cms, file, true);
130     }
131 
132     /**
133      * Factory method to unmarshal (read) a XML content instance from a OpenCms VFS file
134      * that contains XML data, using wither the encoding set
135      * in the XML file header, or the encoding set in the VFS file property.<p>
136      * 
137      * If you are not sure about the implications of the encoding issues, 
138      * use {@link #unmarshal(CmsObject, CmsFile)} instead.<p>
139      * 
140      * @param cms the current cms object
141      * @param file the file with the XML data to unmarshal
142      * @param keepEncoding if true, the encoding spefified in the XML header is used, 
143      *    otherwise the encoding from the VFS file property is used
144      * @return a XML content instance unmarshalled from the provided file
145      * @throws CmsXmlException if something goes wrong
146      */
147     public static CmsXmlContent unmarshal(CmsObject cms, CmsFile file, boolean keepEncoding) throws CmsXmlException {
148 
149         byte[] contentBytes = file.getContents();
150         String   filename = cms.getSitePath(file);
151 
152         String   encoding = null;
153         try {
154             encoding = cms.readPropertyObject(filename, CmsPropertyDefinition.PROPERTY_CONTENT_ENCODING, true).getValue();
155         } catch (CmsException e) {
156             // encoding will be null 
157         }
158         if (encoding == null) {
159             encoding = OpenCms.getSystemInfo().getDefaultEncoding();
160         } else {
161             encoding = CmsEncoder.lookupEncoding(encoding, null);
162             if (encoding == null) {
163                 throw new CmsXmlException(Messages.get().container(Messages.ERR_XMLCONTENT_INVALID_ENC_1, filename));
164             }
165         }
166 
167         CmsXmlContent content;
168         if (contentBytes.length > 0) {
169             // content is initialized
170             if (keepEncoding) {
171                 // use the encoding from the content
172                 content = unmarshal(contentBytes, encoding, new CmsXmlEntityResolver(cms));
173             } else {
174                 // use the encoding from the file property
175                 // this usually only triggered by a save operation                
176                 try {
177                     String   contentStr = new String  (contentBytes, encoding);
178                     content = unmarshal(contentStr, encoding, new CmsXmlEntityResolver(cms));
179                 } catch (UnsupportedEncodingException   e) {
180                     // this will not happen since the encodig has already been validated
181                     throw new CmsXmlException(Messages.get().container(Messages.ERR_XMLCONTENT_INVALID_ENC_1, filename));
182                 }
183             }
184         } else {
185             // content is empty
186             content = new CmsXmlContent(DocumentHelper.createDocument(), encoding, new CmsXmlEntityResolver(cms));
187         }
188 
189         // set the file
190         content.setFile(file);
191         // return the result
192         return content;
193     }
194 
195     /**
196      * Factory method to unmarshal (read) a XML content instance from
197      * a resource, using the request attributes as cache.<p>
198      * 
199      * @param cms the current OpenCms context object
200      * @param resource the resource to unmarshal
201      * @param req the current request
202      * 
203      * @return the unmarshaled xml content, or null if the given resource was not of type {@link org.opencms.file.types.CmsResourceTypeXmlContent}
204      * 
205      * @throws CmsException in something goes wrong
206      * @throws CmsLoaderException if no loader for the given <code>resource</code> type ({@link CmsResource#getTypeId()}) is available
207      * @throws CmsXmlException if the given <code>resource</code> is not of type xml content
208      */
209     public static CmsXmlContent unmarshal(CmsObject cms, CmsResource resource, ServletRequest   req)
210     throws CmsXmlException, CmsLoaderException, CmsException {
211 
212         String   rootPath = resource.getRootPath();
213 
214         if (!(OpenCms.getResourceManager().getLoader(resource) instanceof CmsXmlContentLoader)) {
215             // sanity check: resource must be of type XML content
216             throw new CmsXmlException(Messages.get().container(
217                 Messages.ERR_XMLCONTENT_INVALID_TYPE_1,
218                 cms.getSitePath(resource)));
219         }
220 
221         // try to get the requested content form the current request attributes 
222         CmsXmlContent content = (CmsXmlContent)req.getAttribute(rootPath);
223 
224         if (content == null) {
225             // unmarshal XML structure from the file content
226             content = unmarshal(cms, CmsFile.upgrade(resource, cms));
227             // store the content as request attribute for future read requests
228             req.setAttribute(rootPath, content);
229         }
230 
231         // return the result
232         return content;
233     }
234 
235     /**
236      * Factory method to unmarshal (generate) a XML content instance from a XML document.<p>
237      * 
238      * The given encoding is used when marshalling the XML again later.<p>
239      * 
240      * @param document the XML document to generate the XML content from
241      * @param encoding the encoding to use when marshalling the XML content later
242      * @param resolver the XML entitiy resolver to use
243      * @return a XML content instance unmarshalled from the String
244      */
245     public static CmsXmlContent unmarshal(Document document, String   encoding, EntityResolver resolver) {
246 
247         return new CmsXmlContent(document, encoding, resolver);
248     }
249 
250     /**
251      * Factory method to unmarshal (generate) a XML content instance from a String
252      * that contains XML data.<p>
253      * 
254      * The given encoding is used when marshalling the XML again later.<p>
255      * 
256      * @param xmlData the XML data in a String
257      * @param encoding the encoding to use when marshalling the XML content later
258      * @param resolver the XML entitiy resolver to use
259      * @return a XML content instance unmarshalled from the String
260      * @throws CmsXmlException if something goes wrong
261      */
262     public static CmsXmlContent unmarshal(String   xmlData, String   encoding, EntityResolver resolver)
263     throws CmsXmlException {
264 
265         // create the XML content object from the provided String
266         CmsXmlContent content = unmarshal(CmsXmlUtils.unmarshalHelper(xmlData, resolver), encoding, resolver);
267         // return the result with the user context set
268         return content;
269 
270     }
271 }
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