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 */
17package org.apache.commons.io;
18
19import 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 * {@link javax.servlet.ServletContextListener#contextDestroyed} or similar.
34 *
35 * @author Noel Bergman
36 * @author Martin Cooper
37 * @version $Id: FileCleaner.java 553012 2007-07-03 23:01:07Z ggregory $
38 * @deprecated Use {@link FileCleaningTracker}
39 */
40@Deprecated
41public class FileCleaner {
42    /**
43     * The instance to use for the deprecated, static methods.
44     */
45    static final FileCleaningTracker theInstance = new FileCleaningTracker();
46
47    //-----------------------------------------------------------------------
48    /**
49     * Track the specified file, using the provided marker, deleting the file
50     * when the marker instance is garbage collected.
51     * The {@link FileDeleteStrategy#NORMAL normal} deletion strategy will be used.
52     *
53     * @param file  the file to be tracked, not null
54     * @param marker  the marker object used to track the file, not null
55     * @throws NullPointerException if the file is null
56     * @deprecated Use {@link FileCleaningTracker#track(File, Object)}.
57     */
58    @Deprecated
59    public static void track(File file, Object marker) {
60        theInstance.track(file, marker);
61    }
62
63    /**
64     * Track the specified file, using the provided marker, deleting the file
65     * when the marker instance is garbage collected.
66     * The speified deletion strategy is used.
67     *
68     * @param file  the file to be tracked, not null
69     * @param marker  the marker object used to track the file, not null
70     * @param deleteStrategy  the strategy to delete the file, null means normal
71     * @throws NullPointerException if the file is null
72     * @deprecated Use {@link FileCleaningTracker#track(File, Object, FileDeleteStrategy)}.
73     */
74    @Deprecated
75    public static void track(File file, Object marker, FileDeleteStrategy deleteStrategy) {
76        theInstance.track(file, marker, deleteStrategy);
77    }
78
79    /**
80     * Track the specified file, using the provided marker, deleting the file
81     * when the marker instance is garbage collected.
82     * The {@link FileDeleteStrategy#NORMAL normal} deletion strategy will be used.
83     *
84     * @param path  the full path to the file to be tracked, not null
85     * @param marker  the marker object used to track the file, not null
86     * @throws NullPointerException if the path is null
87     * @deprecated Use {@link FileCleaningTracker#track(String, Object)}.
88     */
89    @Deprecated
90    public static void track(String path, Object marker) {
91        theInstance.track(path, marker);
92    }
93
94    /**
95     * Track the specified file, using the provided marker, deleting the file
96     * when the marker instance is garbage collected.
97     * The speified deletion strategy is used.
98     *
99     * @param path  the full path to the file to be tracked, not null
100     * @param marker  the marker object used to track the file, not null
101     * @param deleteStrategy  the strategy to delete the file, null means normal
102     * @throws NullPointerException if the path is null
103     * @deprecated Use {@link FileCleaningTracker#track(String, Object, FileDeleteStrategy)}.
104     */
105    @Deprecated
106    public static void track(String path, Object marker, FileDeleteStrategy deleteStrategy) {
107        theInstance.track(path, marker, deleteStrategy);
108    }
109
110    //-----------------------------------------------------------------------
111    /**
112     * Retrieve the number of files currently being tracked, and therefore
113     * awaiting deletion.
114     *
115     * @return the number of files being tracked
116     * @deprecated Use {@link FileCleaningTracker#getTrackCount()}.
117     */
118    @Deprecated
119    public static int getTrackCount() {
120        return theInstance.getTrackCount();
121    }
122
123    /**
124     * Call this method to cause the file cleaner thread to terminate when
125     * there are no more objects being tracked for deletion.
126     * <p>
127     * In a simple environment, you don't need this method as the file cleaner
128     * thread will simply exit when the JVM exits. In a more complex environment,
129     * with multiple class loaders (such as an application server), you should be
130     * aware that the file cleaner thread will continue running even if the class
131     * loader it was started from terminates. This can consitute a memory leak.
132     * <p>
133     * For example, suppose that you have developed a web application, which
134     * contains the commons-io jar file in your WEB-INF/lib directory. In other
135     * words, the FileCleaner class is loaded through the class loader of your
136     * web application. If the web application is terminated, but the servlet
137     * container is still running, then the file cleaner thread will still exist,
138     * posing a memory leak.
139     * <p>
140     * This method allows the thread to be terminated. Simply call this method
141     * in the resource cleanup code, such as {@link javax.servlet.ServletContextListener#contextDestroyed}.
142     * One called, no new objects can be tracked by the file cleaner.
143     * @deprecated Use {@link FileCleaningTracker#exitWhenFinished()}.
144     */
145    @Deprecated
146    public static synchronized void exitWhenFinished() {
147        theInstance.exitWhenFinished();
148    }
149
150    /**
151     * Returns the singleton instance, which is used by the deprecated, static methods.
152     * This is mainly useful for code, which wants to support the new
153     * {@link FileCleaningTracker} class while maintain compatibility with the
154     * deprecated {@link FileCleaner}.
155     *
156     * @return the singleton instance
157     */
158    public static FileCleaningTracker getInstance() {
159        return theInstance;
160    }
161}
162