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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.apache.commons.vfs.provider.url;
18  
19  import org.apache.commons.vfs.Capability;
20  import org.apache.commons.vfs.FileName;
21  import org.apache.commons.vfs.FileObject;
22  import org.apache.commons.vfs.FileSystem;
23  import org.apache.commons.vfs.FileSystemConfigBuilder;
24  import org.apache.commons.vfs.FileSystemException;
25  import org.apache.commons.vfs.FileSystemOptions;
26  import org.apache.commons.vfs.provider.AbstractFileProvider;
27  
28  import java.net.MalformedURLException;
29  import java.net.URL;
30  import java.util.Arrays;
31  import java.util.Collection;
32  import java.util.Collections;
33  
34  /***
35   * A file provider backed by Java's URL API.
36   *
37   * @author <a href="mailto:adammurdoch@apache.org">Adam Murdoch</a>
38   * @version $Revision: 480428 $ $Date: 2006-11-29 07:15:24 +0100 (Mi, 29 Nov 2006) $
39   */
40  public class UrlFileProvider
41      extends AbstractFileProvider
42  {
43      protected final static Collection capabilities = Collections.unmodifiableCollection(Arrays.asList(new Capability[]
44      {
45          Capability.READ_CONTENT,
46          Capability.URI,
47          Capability.GET_LAST_MODIFIED
48      }));
49  
50      public UrlFileProvider()
51      {
52          super();
53          setFileNameParser(new UrlFileNameParser());
54      }
55  
56      /***
57       * Locates a file object, by absolute URI.
58       */
59      public synchronized FileObject findFile(final FileObject baseFile,
60                                              final String uri,
61                                              final FileSystemOptions fileSystemOptions)
62          throws FileSystemException
63      {
64          try
65          {
66              final URL url = new URL(uri);
67  
68              URL rootUrl = new URL(url, "/");
69              final String key = this.getClass().getName() + rootUrl.toString();
70              FileSystem fs = findFileSystem(key, fileSystemOptions);
71              if (fs == null)
72              {
73                  String extForm = rootUrl.toExternalForm();
74                  final FileName rootName =
75                      getContext().parseURI(extForm);
76                  // final FileName rootName =
77                  //    new BasicFileName(rootUrl, FileName.ROOT_PATH);
78                  fs = new UrlFileSystem(rootName, fileSystemOptions);
79                  addFileSystem(key, fs);
80              }
81              return fs.resolveFile(url.getPath());
82          }
83          catch (final MalformedURLException e)
84          {
85              throw new FileSystemException("vfs.provider.url/badly-formed-uri.error", uri, e);
86          }
87      }
88  
89      public FileSystemConfigBuilder getConfigBuilder()
90      {
91          return org.apache.commons.vfs.provider.res.ResourceFileSystemConfigBuilder.getInstance();
92      }
93  
94      public Collection getCapabilities()
95      {
96          return capabilities;
97      }
98  }