DeleteOnExitHook.java revision 3d43823e17818b3c5f45831f830884917b181454 
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        // Android-changed: Access java.lang.Shutdown directly.
40        java.lang.Shutdown.add(2, true,
41                new Runnable() {
42                    public void run() {
43                       runHooks();
44                    }
45                }
46        );
47    }
48
49    private DeleteOnExitHook() {}
50
51    static synchronized void add(String file) {
52        if(files == null) {
53            // DeleteOnExitHook is running. Too late to add a file
54            throw new IllegalStateException("Shutdown in progress");
55        }
56
57        files.add(file);
58    }
59
60    static void runHooks() {
61        LinkedHashSet<String> theFiles;
62
63        synchronized (DeleteOnExitHook.class) {
64            theFiles = files;
65            files = null;
66        }
67
68        ArrayList<String> toBeDeleted = new ArrayList<>(theFiles);
69
70        // reverse the list to maintain previous jdk deletion order.
71        // Last in first deleted.
72        Collections.reverse(toBeDeleted);
73        for (String filename : toBeDeleted) {
74            (new File(filename)).delete();
75        }
76    }
77}
78