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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.filter;
18  
19  import java.io.Serializable;
20  
21  import org.apache.commons.vfs2.FileFilter;
22  import org.apache.commons.vfs2.FileSelectInfo;
23  import org.apache.commons.vfs2.FileSystemException;
24  import org.apache.commons.vfs2.FileType;
25  
26  /**
27   * This filter accepts {@code File}s that are directories.
28   * <p>
29   * For example, here is how to print out a list of the current directory's sub
30   * directories:
31   * </p>
32   *
33   * <pre>
34   * FileSystemManager fsManager = VFS.getManager();
35   * FileObject dir = fsManager.toFileObject(new File(&quot;.&quot;));
36   * FileObject[] files = dir.findFiles(new FileFilterSelector(DirectoryFileFilter.DIRECTORY));
37   * for (int i = 0; i &lt; files.length; i++) {
38   *     System.out.println(files[i]);
39   * }
40   * </pre>
41   *
42   * @author This code was originally ported from Apache Commons IO File Filter
43   * @see "http://commons.apache.org/proper/commons-io/"
44   * @since 2.4
45   */
46  public class DirectoryFileFilter implements FileFilter, Serializable {
47  
48      private static final long serialVersionUID = 1L;
49  
50      /**
51       * Singleton instance of directory filter.
52       */
53      public static final FileFilter DIRECTORY = new DirectoryFileFilter();
54  
55      /**
56       * Restrictive constructor.
57       */
58      protected DirectoryFileFilter() {
59      }
60  
61      /**
62       * Checks to see if the file is a directory.
63       *
64       * @param fileSelectInfo the File to check
65       *
66       * @return {@code true} if the file is a directory
67       * @throws FileSystemException Thrown for file system errors.
68       */
69      @Override
70      public boolean accept(final FileSelectInfo fileSelectInfo) throws FileSystemException {
71          return fileSelectInfo.getFile().getType() == FileType.FOLDER;
72      }
73  
74  }