1/*
2 * Copyright (c) 2011, 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 sun.nio.fs;
27
28import java.nio.file.Path;
29import java.nio.file.LinkOption;
30import java.nio.file.attribute.BasicFileAttributes;
31import java.nio.file.spi.FileSystemProvider;
32import java.io.IOException;
33import java.util.Map;
34
35/**
36 * Base implementation class of FileSystemProvider
37 */
38
39public abstract class AbstractFileSystemProvider extends FileSystemProvider {
40    protected AbstractFileSystemProvider() { }
41
42    /**
43     * Splits the given attribute name into the name of an attribute view and
44     * the attribute. If the attribute view is not identified then it assumed
45     * to be "basic".
46     */
47    private static String[] split(String attribute) {
48        String[] s = new String[2];
49        int pos = attribute.indexOf(':');
50        if (pos == -1) {
51            s[0] = "basic";
52            s[1] = attribute;
53        } else {
54            s[0] = attribute.substring(0, pos++);
55            s[1] = (pos == attribute.length()) ? "" : attribute.substring(pos);
56        }
57        return s;
58    }
59
60    /**
61     * Gets a DynamicFileAttributeView by name. Returns {@code null} if the
62     * view is not available.
63     */
64    abstract DynamicFileAttributeView getFileAttributeView(Path file,
65                                                           String name,
66                                                           LinkOption... options);
67
68    @Override
69    public final void setAttribute(Path file,
70                                   String attribute,
71                                   Object value,
72                                   LinkOption... options)
73        throws IOException
74    {
75        String[] s = split(attribute);
76        if (s[0].length() == 0)
77            throw new IllegalArgumentException(attribute);
78        DynamicFileAttributeView view = getFileAttributeView(file, s[0], options);
79        if (view == null)
80            throw new UnsupportedOperationException("View '" + s[0] + "' not available");
81        view.setAttribute(s[1], value);
82    }
83
84    @Override
85    public final Map<String,Object> readAttributes(Path file, String attributes, LinkOption... options)
86        throws IOException
87    {
88        String[] s = split(attributes);
89        if (s[0].length() == 0)
90            throw new IllegalArgumentException(attributes);
91        DynamicFileAttributeView view = getFileAttributeView(file, s[0], options);
92        if (view == null)
93            throw new UnsupportedOperationException("View '" + s[0] + "' not available");
94        return view.readAttributes(s[1].split(","));
95    }
96
97    /**
98     * Deletes a file. The {@code failIfNotExists} parameters determines if an
99     * {@code IOException} is thrown when the file does not exist.
100     */
101    abstract boolean implDelete(Path file, boolean failIfNotExists) throws IOException;
102
103    @Override
104    public final void delete(Path file) throws IOException {
105        implDelete(file, true);
106    }
107
108    @Override
109    public final boolean deleteIfExists(Path file) throws IOException {
110        return implDelete(file, false);
111    }
112
113    /**
114     * Tests whether a file is a directory.
115     *
116     * @return  {@code true} if the file is a directory; {@code false} if
117     *          the file does not exist, is not a directory, or it cannot
118     *          be determined if the file is a directory or not.
119     */
120    public boolean isDirectory(Path file) {
121        try {
122            return readAttributes(file, BasicFileAttributes.class).isDirectory();
123        } catch (IOException ioe) {
124            return false;
125        }
126    }
127
128    /**
129     * Tests whether a file is a regular file with opaque content.
130     *
131     * @return  {@code true} if the file is a regular file; {@code false} if
132     *          the file does not exist, is not a regular file, or it
133     *          cannot be determined if the file is a regular file or not.
134     */
135    public boolean isRegularFile(Path file) {
136        try {
137            return readAttributes(file, BasicFileAttributes.class).isRegularFile();
138        } catch (IOException ioe) {
139            return false;
140        }
141    }
142
143    /**
144     * Checks the existence of a file.
145     *
146     * @return  {@code true} if the file exists; {@code false} if the file does
147     *          not exist or its existence cannot be determined.
148     */
149    public boolean exists(Path file) {
150        try {
151            checkAccess(file);
152            return true;
153        } catch (IOException ioe) {
154            return false;
155        }
156    }
157}
158