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 18 package org.apache.harmony.luni.util; 19 20 21 import java.io.File; 22 import java.util.ArrayList; 23 import java.util.Collections; 24 25 // BEGIN android-changed 26 /** 27 * Implements the actual DeleteOnExit mechanism. Is registered as a shutdown 28 * hook in the Runtime, once it is actually being used. 29 */ 30 public class DeleteOnExit extends Thread { 31 32 /** 33 * Our singleton instance. 34 */ 35 private static DeleteOnExit instance; 36 37 /** 38 * Our list of files scheduled for deletion. 39 */ 40 private ArrayList<String> files = new ArrayList<String>(); 41 42 /** 43 * Returns our singleton instance, creating it if necessary. 44 */ getInstance()45 public static synchronized DeleteOnExit getInstance() { 46 if (instance == null) { 47 instance = new DeleteOnExit(); 48 Runtime.getRuntime().addShutdownHook(instance); 49 } 50 51 return instance; 52 } 53 54 /** 55 * Schedules a file for deletion. 56 * 57 * @param filename The file to delete. 58 */ addFile(String filename)59 public void addFile(String filename) { 60 synchronized(files) { 61 if (!files.contains(filename)) { 62 files.add(filename); 63 } 64 } 65 } 66 67 /** 68 * Does the actual work. Note we (a) first sort the files lexicographically 69 * and then (b) delete them in reverse order. This is to make sure files 70 * get deleted before their parent directories. 71 */ 72 @Override run()73 public void run() { 74 Collections.sort(files); 75 for (int i = files.size() - 1; i >= 0; i--) { 76 new File(files.get(i)).delete(); 77 } 78 } 79 } 80 // END android-changed 81