1/*
2 * Copyright (c) 2004, 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
26package jdk.internal.agent;
27
28import java.io.File;
29import java.io.IOException;
30
31/*
32 * Utility class to support file system operations
33 *
34 * @since 1.5
35 */
36public abstract class FileSystem {
37
38    private static final Object lock = new Object();
39    private static FileSystem fs;
40
41    protected FileSystem() { }
42
43    /**
44     * Opens the file system
45     */
46    public static FileSystem open() {
47        synchronized (lock) {
48            if (fs == null) {
49                fs = new FileSystemImpl();
50            }
51            return fs;
52        }
53    }
54
55    /**
56     * Tells whether or not the specified file is located on a
57     * file system that supports file security or not.
58     *
59     * @throws  IOException     if an I/O error occurs.
60     */
61    public abstract boolean supportsFileSecurity(File f) throws IOException;
62
63    /**
64     * Tell whether or not the specified file is accessible
65     * by anything other than the file owner.
66     *
67     * @throws  IOException     if an I/O error occurs.
68     *
69     * @throws  UnsupportedOperationException
70     *          If file is located on a file system that doesn't support
71     *          file security.
72     */
73    public abstract boolean isAccessUserOnly(File f) throws IOException;
74}
75