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 * @deprecated Use {@link FileCleaningTracker} 036 */ 037@Deprecated 038public class FileCleaner { 039 /** 040 * The instance to use for the deprecated, static methods. 041 */ 042 static final FileCleaningTracker theInstance = new FileCleaningTracker(); 043 044 /** 045 * Track the specified file, using the provided marker, deleting the file 046 * when the marker instance is garbage collected. 047 * The {@link FileDeleteStrategy#NORMAL normal} deletion strategy will be used. 048 * 049 * @param file the file to be tracked, not null 050 * @param marker the marker object used to track the file, not null 051 * @throws NullPointerException if the file is null 052 * @deprecated Use {@link FileCleaningTracker#track(File, Object)}. 053 */ 054 @Deprecated 055 public static void track(final File file, final Object marker) { 056 theInstance.track(file, marker); 057 } 058 059 /** 060 * Track the specified file, using the provided marker, deleting the file 061 * when the marker instance is garbage collected. 062 * The specified deletion strategy is used. 063 * 064 * @param file the file to be tracked, not null 065 * @param marker the marker object used to track the file, not null 066 * @param deleteStrategy the strategy to delete the file, null means normal 067 * @throws NullPointerException if the file is null 068 * @deprecated Use {@link FileCleaningTracker#track(File, Object, FileDeleteStrategy)}. 069 */ 070 @Deprecated 071 public static void track(final File file, final Object marker, final FileDeleteStrategy deleteStrategy) { 072 theInstance.track(file, marker, deleteStrategy); 073 } 074 075 /** 076 * Track the specified file, using the provided marker, deleting the file 077 * when the marker instance is garbage collected. 078 * The {@link FileDeleteStrategy#NORMAL normal} deletion strategy will be used. 079 * 080 * @param path the full path to the file to be tracked, not null 081 * @param marker the marker object used to track the file, not null 082 * @throws NullPointerException if the path is null 083 * @deprecated Use {@link FileCleaningTracker#track(String, Object)}. 084 */ 085 @Deprecated 086 public static void track(final String path, final 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 specified 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 @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}