001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.commons.io;
018
019 import java.io.File;
020
021 /**
022 * Keeps track of files awaiting deletion, and deletes them when an associated
023 * marker object is reclaimed by the garbage collector.
024 * <p>
025 * This utility creates a background thread to handle file deletion.
026 * Each file to be deleted is registered with a handler object.
027 * When the handler object is garbage collected, the file is deleted.
028 * <p>
029 * In an environment with multiple class loaders (a servlet container, for
030 * example), you should consider stopping the background thread if it is no
031 * longer needed. This is done by invoking the method
032 * {@link #exitWhenFinished}, typically in
033 * {@link javax.servlet.ServletContextListener#contextDestroyed} or similar.
034 *
035 * @author Noel Bergman
036 * @author Martin Cooper
037 * @version $Id: FileCleaner.java 553012 2007-07-03 23:01:07Z ggregory $
038 * @deprecated Use {@link FileCleaningTracker}
039 */
040 public class FileCleaner {
041 /**
042 * The instance to use for the deprecated, static methods.
043 */
044 static final FileCleaningTracker theInstance = new FileCleaningTracker();
045
046 //-----------------------------------------------------------------------
047 /**
048 * Track the specified file, using the provided marker, deleting the file
049 * when the marker instance is garbage collected.
050 * The {@link FileDeleteStrategy#NORMAL normal} deletion strategy will be used.
051 *
052 * @param file the file to be tracked, not null
053 * @param marker the marker object used to track the file, not null
054 * @throws NullPointerException if the file is null
055 * @deprecated Use {@link FileCleaningTracker#track(File, Object)}.
056 */
057 public static void track(File file, Object marker) {
058 theInstance.track(file, marker);
059 }
060
061 /**
062 * Track the specified file, using the provided marker, deleting the file
063 * when the marker instance is garbage collected.
064 * The speified deletion strategy is used.
065 *
066 * @param file the file to be tracked, not null
067 * @param marker the marker object used to track the file, not null
068 * @param deleteStrategy the strategy to delete the file, null means normal
069 * @throws NullPointerException if the file is null
070 * @deprecated Use {@link FileCleaningTracker#track(File, Object, FileDeleteStrategy)}.
071 */
072 public static void track(File file, Object marker, FileDeleteStrategy deleteStrategy) {
073 theInstance.track(file, marker, deleteStrategy);
074 }
075
076 /**
077 * Track the specified file, using the provided marker, deleting the file
078 * when the marker instance is garbage collected.
079 * The {@link FileDeleteStrategy#NORMAL normal} deletion strategy will be used.
080 *
081 * @param path the full path to the file to be tracked, not null
082 * @param marker the marker object used to track the file, not null
083 * @throws NullPointerException if the path is null
084 * @deprecated Use {@link FileCleaningTracker#track(String, Object)}.
085 */
086 public static void track(String path, Object marker) {
087 theInstance.track(path, marker);
088 }
089
090 /**
091 * Track the specified file, using the provided marker, deleting the file
092 * when the marker instance is garbage collected.
093 * The speified deletion strategy is used.
094 *
095 * @param path the full path to the file to be tracked, not null
096 * @param marker the marker object used to track the file, not null
097 * @param deleteStrategy the strategy to delete the file, null means normal
098 * @throws NullPointerException if the path is null
099 * @deprecated Use {@link FileCleaningTracker#track(String, Object, FileDeleteStrategy)}.
100 */
101 public static void track(String path, Object marker, FileDeleteStrategy deleteStrategy) {
102 theInstance.track(path, marker, deleteStrategy);
103 }
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 public static int getTrackCount() {
114 return theInstance.getTrackCount();
115 }
116
117 /**
118 * Call this method to cause the file cleaner thread to terminate when
119 * there are no more objects being tracked for deletion.
120 * <p>
121 * In a simple environment, you don't need this method as the file cleaner
122 * thread will simply exit when the JVM exits. In a more complex environment,
123 * with multiple class loaders (such as an application server), you should be
124 * aware that the file cleaner thread will continue running even if the class
125 * loader it was started from terminates. This can consitute a memory leak.
126 * <p>
127 * For example, suppose that you have developed a web application, which
128 * contains the commons-io jar file in your WEB-INF/lib directory. In other
129 * words, the FileCleaner class is loaded through the class loader of your
130 * web application. If the web application is terminated, but the servlet
131 * container is still running, then the file cleaner thread will still exist,
132 * posing a memory leak.
133 * <p>
134 * This method allows the thread to be terminated. Simply call this method
135 * in the resource cleanup code, such as {@link javax.servlet.ServletContextListener#contextDestroyed}.
136 * One called, no new objects can be tracked by the file cleaner.
137 * @deprecated Use {@link FileCleaningTracker#exitWhenFinished()}.
138 */
139 public static synchronized void exitWhenFinished() {
140 theInstance.exitWhenFinished();
141 }
142
143 /**
144 * Returns the singleton instance, which is used by the deprecated, static methods.
145 * This is mainly useful for code, which wants to support the new
146 * {@link FileCleaningTracker} class while maintain compatibility with the
147 * deprecated {@link FileCleaner}.
148 *
149 * @return the singleton instance
150 */
151 public static FileCleaningTracker getInstance() {
152 return theInstance;
153 }
154 }