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;
18
19 import org.apache.commons.vfs2.FileName;
20 import org.apache.commons.vfs2.FileObject;
21 import org.apache.commons.vfs2.FileSystem;
22 import org.apache.commons.vfs2.FileSystemException;
23 import org.apache.commons.vfs2.FileSystemOptions;
24
25 /**
26 * A {@link FileProvider} that is layered on top of another, such as the contents of a zip or tar file.
27 */
28 public abstract class AbstractLayeredFileProvider extends AbstractFileProvider {
29
30 public AbstractLayeredFileProvider() {
31 setFileNameParser(LayeredFileNameParser.getInstance());
32 }
33
34 /**
35 * Locates a file object, by absolute URI.
36 *
37 * @param baseFile The base FileObject.
38 * @param uri The name of the file to locate.
39 * @param fileSystemOptions The FileSystemOptions.
40 * @return The FileObject if it is located, null otherwise.
41 * @throws FileSystemException if an error occurs.
42 */
43 @Override
44 public FileObjectect.html#FileObject">FileObject findFile(final FileObject baseFile, final String uri, final FileSystemOptions fileSystemOptions)
45 throws FileSystemException {
46 // Split the URI up into its parts
47 final LayeredFileName./../../org/apache/commons/vfs2/provider/LayeredFileName.html#LayeredFileName">LayeredFileName name = (LayeredFileName) parseUri(baseFile != null ? baseFile.getName() : null, uri);
48
49 // Make the URI canonical
50
51 // Resolve the outer file name
52 final FileName fileName = name.getOuterName();
53 final FileObject file = getContext().resolveFile(baseFile, fileName.getURI(), fileSystemOptions);
54
55 // Create the file system
56 final FileObject rootFile = createFileSystem(name.getScheme(), file, fileSystemOptions);
57
58 // Resolve the file
59 return rootFile.resolveFile(name.getPath());
60 }
61
62 /**
63 * Creates a layered file system.
64 *
65 * @param scheme The protocol to use.
66 * @param file a FileObject.
67 * @param fileSystemOptions Options to access the FileSystem.
68 * @return A FileObject associated with the new FileSystem.
69 * @throws FileSystemException if an error occurs.
70 */
71 @Override
72 public synchronized FileObject createFileSystem(FileObject="jxr_keyword">final String scheme, final FileObject file,
73 final FileSystemOptions fileSystemOptions) throws FileSystemException {
74 // Check if cached
75 final FileName rootName = file.getName();
76 FileSystem fs = findFileSystem(rootName, fileSystemOptions);
77 if (fs == null) {
78 // Create the file system
79 fs = doCreateFileSystem(scheme, file, fileSystemOptions);
80 addFileSystem(rootName, fs);
81 }
82 return fs.getRoot();
83 }
84
85 /**
86 * Creates a layered file system.
87 * <p>
88 * This method is called if the file system is not cached.
89 * </p>
90 *
91 * @param scheme The URI scheme.
92 * @param file The file to create the file system on top of.
93 * @param fileSystemOptions options for new and underlying file systems.
94 * @return The file system, never null. Might implement {@link VfsComponent}.
95 * @throws FileSystemException if the file system cannot be created.
96 */
97 protected abstract FileSystem doCreateFileSystem(final String scheme, final FileObject file,
98 final FileSystemOptions fileSystemOptions) throws FileSystemException;
99
100 }