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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.io;
18  
19  import java.io.File;
20  
21  /**
22   * Keeps track of files awaiting deletion, and deletes them when an associated
23   * marker object is reclaimed by the garbage collector.
24   * <p>
25   * This utility creates a background thread to handle file deletion.
26   * Each file to be deleted is registered with a handler object.
27   * When the handler object is garbage collected, the file is deleted.
28   * <p>
29   * In an environment with multiple class loaders (a servlet container, for
30   * example), you should consider stopping the background thread if it is no
31   * longer needed. This is done by invoking the method
32   * {@link #exitWhenFinished}, typically in
33   * {@code javax.servlet.ServletContextListener.contextDestroyed(javax.servlet.ServletContextEvent)} or similar.
34   *
35   * @deprecated Use {@link FileCleaningTracker}
36   */
37  @Deprecated
38  public class FileCleaner {
39      /**
40       * The instance to use for the deprecated, static methods.
41       */
42      static final FileCleaningTracker#FileCleaningTracker">FileCleaningTracker theInstance = new FileCleaningTracker();
43  
44      /**
45       * Track the specified file, using the provided marker, deleting the file
46       * when the marker instance is garbage collected.
47       * The {@link FileDeleteStrategy#NORMAL normal} deletion strategy will be used.
48       *
49       * @param file  the file to be tracked, not null
50       * @param marker  the marker object used to track the file, not null
51       * @throws NullPointerException if the file is null
52       * @deprecated Use {@link FileCleaningTracker#track(File, Object)}.
53       */
54      @Deprecated
55      public static void track(final File file, final Object marker) {
56          theInstance.track(file, marker);
57      }
58  
59      /**
60       * Track the specified file, using the provided marker, deleting the file
61       * when the marker instance is garbage collected.
62       * The specified deletion strategy is used.
63       *
64       * @param file  the file to be tracked, not null
65       * @param marker  the marker object used to track the file, not null
66       * @param deleteStrategy  the strategy to delete the file, null means normal
67       * @throws NullPointerException if the file is null
68       * @deprecated Use {@link FileCleaningTracker#track(File, Object, FileDeleteStrategy)}.
69       */
70      @Deprecated
71      public static void track(final File file, final Object marker, final FileDeleteStrategy deleteStrategy) {
72          theInstance.track(file, marker, deleteStrategy);
73      }
74  
75      /**
76       * Track the specified file, using the provided marker, deleting the file
77       * when the marker instance is garbage collected.
78       * The {@link FileDeleteStrategy#NORMAL normal} deletion strategy will be used.
79       *
80       * @param path  the full path to the file to be tracked, not null
81       * @param marker  the marker object used to track the file, not null
82       * @throws NullPointerException if the path is null
83       * @deprecated Use {@link FileCleaningTracker#track(String, Object)}.
84       */
85      @Deprecated
86      public static void track(final String path, final Object marker) {
87          theInstance.track(path, marker);
88      }
89  
90      /**
91       * Track the specified file, using the provided marker, deleting the file
92       * when the marker instance is garbage collected.
93       * The specified deletion strategy is used.
94       *
95       * @param path  the full path to the file to be tracked, not null
96       * @param marker  the marker object used to track the file, not null
97       * @param deleteStrategy  the strategy to delete the file, null means normal
98       * @throws NullPointerException if the path is null
99       * @deprecated Use {@link FileCleaningTracker#track(String, Object, FileDeleteStrategy)}.
100      */
101     @Deprecated
102     public static void track(final String path, final Object marker, final FileDeleteStrategy deleteStrategy) {
103         theInstance.track(path, marker, deleteStrategy);
104     }
105 
106     /**
107      * Retrieve the number of files currently being tracked, and therefore
108      * awaiting deletion.
109      *
110      * @return the number of files being tracked
111      * @deprecated Use {@link FileCleaningTracker#getTrackCount()}.
112      */
113     @Deprecated
114     public static int getTrackCount() {
115         return theInstance.getTrackCount();
116     }
117 
118     /**
119      * Call this method to cause the file cleaner thread to terminate when
120      * there are no more objects being tracked for deletion.
121      * <p>
122      * In a simple environment, you don't need this method as the file cleaner
123      * thread will simply exit when the JVM exits. In a more complex environment,
124      * with multiple class loaders (such as an application server), you should be
125      * aware that the file cleaner thread will continue running even if the class
126      * loader it was started from terminates. This can constitute a memory leak.
127      * <p>
128      * For example, suppose that you have developed a web application, which
129      * contains the commons-io jar file in your WEB-INF/lib directory. In other
130      * words, the FileCleaner class is loaded through the class loader of your
131      * web application. If the web application is terminated, but the servlet
132      * container is still running, then the file cleaner thread will still exist,
133      * posing a memory leak.
134      * <p>
135      * This method allows the thread to be terminated. Simply call this method
136      * in the resource cleanup code, such as
137      * {@code javax.servlet.ServletContextListener.contextDestroyed(javax.servlet.ServletContextEvent)}.
138      * One called, no new objects can be tracked by the file cleaner.
139      * @deprecated Use {@link FileCleaningTracker#exitWhenFinished()}.
140      */
141     @Deprecated
142     public static synchronized void exitWhenFinished() {
143         theInstance.exitWhenFinished();
144     }
145 
146     /**
147      * Returns the singleton instance, which is used by the deprecated, static methods.
148      * This is mainly useful for code, which wants to support the new
149      * {@link FileCleaningTracker} class while maintain compatibility with the
150      * deprecated {@link FileCleaner}.
151      *
152      * @return the singleton instance
153      */
154     public static FileCleaningTracker getInstance() {
155         return theInstance;
156     }
157 }