1 /* 2 * Copyright (c) 2005, 2018, 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 */ 25 package java.io; 26 27 import java.util.*; 28 29 import jdk.internal.access.SharedSecrets; 30 31 /** 32 * This class holds a set of filenames to be deleted on VM exit through a shutdown hook. 33 * A set is used both to prevent double-insertion of the same file as well as offer 34 * quick removal. 35 */ 36 37 class DeleteOnExitHook { 38 private static LinkedHashSet<String> files = new LinkedHashSet<>(); 39 static { 40 // DeleteOnExitHook must be the last shutdown hook to be invoked. 41 // Application shutdown hooks may add the first file to the 42 // delete on exit list and cause the DeleteOnExitHook to be 43 // registered during shutdown in progress. So set the 44 // registerShutdownInProgress parameter to true. 45 SharedSecrets.getJavaLangAccess() 46 .registerShutdownHook(2 /* Shutdown hook invocation order */, 47 true /* register even if shutdown in progress */, 48 new Runnable() { 49 public void run() { 50 runHooks(); 51 } 52 } 53 ); 54 } 55 56 private DeleteOnExitHook() {} 57 58 static synchronized void add(String file) { 59 if(files == null) { 60 // DeleteOnExitHook is running. Too late to add a file 61 throw new IllegalStateException("Shutdown in progress"); 62 } 63 64 files.add(file); 65 } 66 67 static void runHooks() { 68 LinkedHashSet<String> theFiles; 69 70 synchronized (DeleteOnExitHook.class) { 71 theFiles = files; 72 files = null; 73 } 74 75 ArrayList<String> toBeDeleted = new ArrayList<>(theFiles); 76 77 // reverse the list to maintain previous jdk deletion order. 78 // Last in first deleted. 79 Collections.reverse(toBeDeleted); 80 for (String filename : toBeDeleted) { 81 (new File(filename)).delete(); 82 } 83 } 84 }