01 /*
02 * Copyright 2005-2007 Sun Microsystems, Inc. All Rights Reserved.
03 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
04 *
05 * This code is free software; you can redistribute it and/or modify it
06 * under the terms of the GNU General Public License version 2 only, as
07 * published by the Free Software Foundation. Sun designates this
08 * particular file as subject to the "Classpath" exception as provided
09 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any questions.
24 */
25 package java.io;
26
27 import java.util.*;
28 import 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
36 class DeleteOnExitHook {
37 private static DeleteOnExitHook instance = null;
38
39 private static LinkedHashSet<String> files = new LinkedHashSet<String>();
40
41 static DeleteOnExitHook hook() {
42 if (instance == null)
43 instance = new DeleteOnExitHook();
44
45 return instance;
46 }
47
48 private DeleteOnExitHook() {
49 }
50
51 static synchronized void add(String file) {
52 if (files == null)
53 throw new IllegalStateException("Shutdown in progress");
54
55 files.add(file);
56 }
57
58 void run() {
59 LinkedHashSet<String> theFiles;
60
61 synchronized (DeleteOnExitHook.class) {
62 theFiles = files;
63 files = null;
64 }
65
66 ArrayList<String> toBeDeleted = new ArrayList<String>(theFiles);
67
68 // reverse the list to maintain previous jdk deletion order.
69 // Last in first deleted.
70 Collections.reverse(toBeDeleted);
71 for (String filename : toBeDeleted) {
72 (new File(filename)).delete();
73 }
74 }
75 }
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