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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.vfs2.provider.compressed;
18  
19  import java.util.Collection;
20  
21  import org.apache.commons.vfs2.Capability;
22  import org.apache.commons.vfs2.FileName;
23  import org.apache.commons.vfs2.FileObject;
24  import org.apache.commons.vfs2.FileSystem;
25  import org.apache.commons.vfs2.FileSystemException;
26  import org.apache.commons.vfs2.FileSystemOptions;
27  import org.apache.commons.vfs2.FileType;
28  import org.apache.commons.vfs2.provider.AbstractLayeredFileProvider;
29  import org.apache.commons.vfs2.provider.LayeredFileName;
30  
31  /**
32   * A file system provider for compressed files. Provides read-only file systems.
33   */
34  public abstract class CompressedFileFileProvider extends AbstractLayeredFileProvider {
35  
36      /**
37       * Constructs a new instance.
38       */
39      public CompressedFileFileProvider() {
40      }
41  
42      /**
43       * Create a FileSystem.
44       *
45       * @param name a file name.
46       * @param file a file object.
47       * @param fileSystemOptions the file system options.
48       * @return a FileSystem.
49       * @throws FileSystemException if a file system error occurs.
50       */
51      protected abstract FileSystem createFileSystem(FileName name, FileObject file, FileSystemOptions fileSystemOptions) throws FileSystemException;
52  
53      /**
54       * Creates a layered file system. This method is called if the file system is not cached.
55       *
56       * @param scheme The URI scheme.
57       * @param file The file to create the file system on top of.
58       * @return The file system.
59       */
60      @Override
61      protected FileSystem doCreateFileSystem(final String scheme, final FileObject file,
62              final FileSystemOptions fileSystemOptions) throws FileSystemException {
63          final FileName name = new LayeredFileName(scheme, file.getName(), FileName.ROOT_PATH, FileType.FOLDER);
64          return createFileSystem(name, file, fileSystemOptions);
65      }
66  
67      @Override
68      public abstract Collection<Capability> getCapabilities();
69  }