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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;
18  
19  /**
20   * The fileCache interface. Implementations of this interface are expected to be thread safe.
21   */
22  public interface FilesCache {
23  
24      /**
25       * Purges the entries corresponding to the FileSystem.
26       *
27       * @param fileSystem The FileSystem.
28       */
29      void clear(final FileSystem fileSystem);
30  
31      /**
32       * Purges the whole cache.
33       */
34      void close();
35  
36      /**
37       * Retrieves a FileObject from the cache by name.
38       *
39       * @param fileSystem The FileSystem.
40       * @param fileName the name
41       * @return the file object or null if file is not cached
42       */
43      FileObject getFile(final FileSystem fileSystem, final FileName fileName);
44  
45      /**
46       * Adds a FileObject to the cache.
47       *
48       * @param file the file
49       */
50      void putFile(final FileObject file);
51  
52      /**
53       * Adds a FileObject to the cache if it isn't already present.
54       *
55       * @param file the file
56       * @return true if the file was stored, false otherwise.
57       */
58      boolean putFileIfAbsent(final FileObject file);
59  
60      /**
61       * Removes a file from cache.
62       *
63       * @param fileSystem file system
64       * @param name file name
65       */
66      void removeFile(final FileSystem fileSystem, final FileName name);
67  
68      /*
69        If the cache uses timestamps it could use this method to handle updates of them.
70  
71        @param file file name
72       */
73      // public void touchFile(final FileObject file);
74  }