View Javadoc
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.io.filefilter;
18  
19  import java.io.File;
20  import java.io.Serializable;
21  import java.nio.file.FileVisitResult;
22  import java.nio.file.Path;
23  import java.nio.file.attribute.BasicFileAttributes;
24  
25  /**
26   * A file filter that always returns true.
27   * <h2>Deprecating Serialization</h2>
28   * <p>
29   * <em>Serialization is deprecated and will be removed in 3.0.</em>
30   * </p>
31   *
32   * @since 1.0
33   * @see FileFilterUtils#trueFileFilter()
34   */
35  public class TrueFileFilter implements IOFileFilter, Serializable {
36  
37      private static final String TO_STRING = Boolean.TRUE.toString();
38  
39      private static final long serialVersionUID = 8782512160909720199L;
40  
41      /**
42       * Singleton instance of true filter.
43       *
44       * @since 1.3
45       */
46      public static final IOFileFilter TRUE = new TrueFileFilter();
47  
48      /**
49       * Singleton instance of true filter. Please use the identical TrueFileFilter.TRUE constant. The new name is more
50       * JDK 1.5 friendly as it doesn't clash with other values when using static imports.
51       */
52      public static final IOFileFilter INSTANCE = TRUE;
53  
54      /**
55       * Restrictive constructor.
56       */
57      protected TrueFileFilter() {
58      }
59  
60      /**
61       * Returns true.
62       *
63       * @param file the file to check (ignored)
64       * @return true
65       */
66      @Override
67      public boolean accept(final File file) {
68          return true;
69      }
70  
71      /**
72       * Returns true.
73       *
74       * @param dir the directory to check (ignored)
75       * @param name the file name (ignored)
76       * @return true
77       */
78      @Override
79      public boolean accept(final File dir, final String name) {
80          return true;
81      }
82  
83      /**
84       * Returns true.
85       * @param file the file to check (ignored)
86       *
87       * @return true
88       * @since 2.9.0
89       */
90      @Override
91      public FileVisitResult accept(final Path file, final BasicFileAttributes attributes) {
92          return FileVisitResult.CONTINUE;
93      }
94  
95      @Override
96      public IOFileFilter and(final IOFileFilter fileFilter) {
97          // TRUE AND expression <=> expression
98          return fileFilter;
99      }
100 
101     @Override
102     public IOFileFilter negate() {
103         return FalseFileFilter.INSTANCE;
104     }
105 
106     @Override
107     public IOFileFilter or(final IOFileFilter fileFilter) {
108         // TRUE OR expression <=> true
109         return INSTANCE;
110     }
111 
112     @Override
113     public String toString() {
114         return TO_STRING;
115     }
116 }