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 */
017package org.apache.commons.io;
018
019import 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 * {@code javax.servlet.ServletContextListener.contextDestroyed(javax.servlet.ServletContextEvent)} or similar.
034 *
035 * @version $Id: FileCleaner.java 1680650 2015-05-20 18:36:40Z britter $
036 * @deprecated Use {@link FileCleaningTracker}
037 */
038@Deprecated
039public class FileCleaner {
040    /**
041     * The instance to use for the deprecated, static methods.
042     */
043    static final FileCleaningTracker theInstance = new FileCleaningTracker();
044
045    //-----------------------------------------------------------------------
046    /**
047     * Track the specified file, using the provided marker, deleting the file
048     * when the marker instance is garbage collected.
049     * The {@link FileDeleteStrategy#NORMAL normal} deletion strategy will be used.
050     *
051     * @param file  the file to be tracked, not null
052     * @param marker  the marker object used to track the file, not null
053     * @throws NullPointerException if the file is null
054     * @deprecated Use {@link FileCleaningTracker#track(File, Object)}.
055     */
056    @Deprecated
057    public static void track(final File file, final 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    @Deprecated
073    public static void track(final File file, final Object marker, final FileDeleteStrategy deleteStrategy) {
074        theInstance.track(file, marker, deleteStrategy);
075    }
076
077    /**
078     * Track the specified file, using the provided marker, deleting the file
079     * when the marker instance is garbage collected.
080     * The {@link FileDeleteStrategy#NORMAL normal} deletion strategy will be used.
081     *
082     * @param path  the full path to the file to be tracked, not null
083     * @param marker  the marker object used to track the file, not null
084     * @throws NullPointerException if the path is null
085     * @deprecated Use {@link FileCleaningTracker#track(String, Object)}.
086     */
087    @Deprecated
088    public static void track(final String path, final Object marker) {
089        theInstance.track(path, marker);
090    }
091
092    /**
093     * Track the specified file, using the provided marker, deleting the file
094     * when the marker instance is garbage collected.
095     * The speified deletion strategy is used.
096     *
097     * @param path  the full path to the file to be tracked, not null
098     * @param marker  the marker object used to track the file, not null
099     * @param deleteStrategy  the strategy to delete the file, null means normal
100     * @throws NullPointerException if the path is null
101     * @deprecated Use {@link FileCleaningTracker#track(String, Object, FileDeleteStrategy)}.
102     */
103    @Deprecated
104    public static void track(final String path, final Object marker, final FileDeleteStrategy deleteStrategy) {
105        theInstance.track(path, marker, deleteStrategy);
106    }
107
108    //-----------------------------------------------------------------------
109    /**
110     * Retrieve the number of files currently being tracked, and therefore
111     * awaiting deletion.
112     *
113     * @return the number of files being tracked
114     * @deprecated Use {@link FileCleaningTracker#getTrackCount()}.
115     */
116    @Deprecated
117    public static int getTrackCount() {
118        return theInstance.getTrackCount();
119    }
120
121    /**
122     * Call this method to cause the file cleaner thread to terminate when
123     * there are no more objects being tracked for deletion.
124     * <p>
125     * In a simple environment, you don't need this method as the file cleaner
126     * thread will simply exit when the JVM exits. In a more complex environment,
127     * with multiple class loaders (such as an application server), you should be
128     * aware that the file cleaner thread will continue running even if the class
129     * loader it was started from terminates. This can consitute a memory leak.
130     * <p>
131     * For example, suppose that you have developed a web application, which
132     * contains the commons-io jar file in your WEB-INF/lib directory. In other
133     * words, the FileCleaner class is loaded through the class loader of your
134     * web application. If the web application is terminated, but the servlet
135     * container is still running, then the file cleaner thread will still exist,
136     * posing a memory leak.
137     * <p>
138     * This method allows the thread to be terminated. Simply call this method
139     * in the resource cleanup code, such as 
140     * {@code javax.servlet.ServletContextListener.contextDestroyed(javax.servlet.ServletContextEvent)}.
141     * One called, no new objects can be tracked by the file cleaner.
142     * @deprecated Use {@link FileCleaningTracker#exitWhenFinished()}.
143     */
144    @Deprecated
145    public static synchronized void exitWhenFinished() {
146        theInstance.exitWhenFinished();
147    }
148
149    /**
150     * Returns the singleton instance, which is used by the deprecated, static methods.
151     * This is mainly useful for code, which wants to support the new
152     * {@link FileCleaningTracker} class while maintain compatibility with the
153     * deprecated {@link FileCleaner}.
154     * 
155     * @return the singleton instance
156     */
157    public static FileCleaningTracker getInstance() {
158        return theInstance;
159    }
160}