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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  
25  /**
26   * This filter produces a logical NOT of the filters specified.
27   *
28   * @author This code was originally ported from Apache Commons IO File Filter
29   * @see "http://commons.apache.org/proper/commons-io/"
30   * @since 2.4
31   */
32  public class NotFileFilter implements FileFilter, Serializable {
33  
34      private static final long serialVersionUID = 1L;
35  
36      /** The filter. */
37      private final FileFilter filter;
38  
39      /**
40       * Constructs a new file filter that NOTs the result of another filter.
41       *
42       * @param filter the filter, must not be null
43       */
44      public NotFileFilter(final FileFilter filter) {
45          if (filter == null) {
46              throw new IllegalArgumentException("The filter must not be null");
47          }
48          this.filter = filter;
49      }
50  
51      /**
52       * Returns the logical NOT of the underlying filter's return value for the same
53       * File.
54       *
55       * @param fileInfo the File to check
56       *
57       * @return {@code true} if the filter returns {@code false}
58       * @throws FileSystemException Thrown for file system errors.
59       */
60      @Override
61      public boolean accept(final FileSelectInfo fileInfo) throws FileSystemException {
62          return !filter.accept(fileInfo);
63      }
64  
65      /**
66       * Provide a String representation of this file filter.
67       *
68       * @return a String representation
69       */
70      @Override
71      public String toString() {
72          return super.toString() + "(" + filter.toString() + ")";
73      }
74  
75  }