DeleteOnExitHook.java revision 552ce337c6777082f434e4f1696ef02a13d5402a
1/* 2 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25package java.io; 26 27import java.util.*; 28import java.io.File; 29 30/** 31 * This class holds a set of filenames to be deleted on VM exit through a shutdown hook. 32 * A set is used both to prevent double-insertion of the same file as well as offer 33 * quick removal. 34 */ 35 36class DeleteOnExitHook { 37 private static LinkedHashSet<String> files = new LinkedHashSet<>(); 38 static { 39 Runtime.getRuntime().addShutdownHook(new Thread() { 40 public void run() { 41 runHooks(); 42 } 43 }); 44 } 45 46 private DeleteOnExitHook() {} 47 48 static synchronized void add(String file) { 49 if(files == null) { 50 // DeleteOnExitHook is running. Too late to add a file 51 throw new IllegalStateException("Shutdown in progress"); 52 } 53 54 files.add(file); 55 } 56 57 static void runHooks() { 58 LinkedHashSet<String> theFiles; 59 60 synchronized (DeleteOnExitHook.class) { 61 theFiles = files; 62 files = null; 63 } 64 65 ArrayList<String> toBeDeleted = new ArrayList<>(theFiles); 66 67 // reverse the list to maintain previous jdk deletion order. 68 // Last in first deleted. 69 Collections.reverse(toBeDeleted); 70 for (String filename : toBeDeleted) { 71 (new File(filename)).delete(); 72 } 73 } 74} 75