1/*
2 * Copyright (c) 2007, 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 java.nio.file;
27
28import java.nio.file.attribute.BasicFileAttributes;
29import java.io.IOException;
30import java.util.Objects;
31
32/**
33 * A simple visitor of files with default behavior to visit all files and to
34 * re-throw I/O errors.
35 *
36 * <p> Methods in this class may be overridden subject to their general contract.
37 *
38 * @param   <T>     The type of reference to the files
39 *
40 * @since 1.7
41 */
42
43public class SimpleFileVisitor<T> implements FileVisitor<T> {
44    /**
45     * Initializes a new instance of this class.
46     */
47    protected SimpleFileVisitor() {
48    }
49
50    /**
51     * Invoked for a directory before entries in the directory are visited.
52     *
53     * <p> Unless overridden, this method returns {@link FileVisitResult#CONTINUE
54     * CONTINUE}.
55     */
56    @Override
57    public FileVisitResult preVisitDirectory(T dir, BasicFileAttributes attrs)
58        throws IOException
59    {
60        Objects.requireNonNull(dir);
61        Objects.requireNonNull(attrs);
62        return FileVisitResult.CONTINUE;
63    }
64
65    /**
66     * Invoked for a file in a directory.
67     *
68     * <p> Unless overridden, this method returns {@link FileVisitResult#CONTINUE
69     * CONTINUE}.
70     */
71    @Override
72    public FileVisitResult visitFile(T file, BasicFileAttributes attrs)
73        throws IOException
74    {
75        Objects.requireNonNull(file);
76        Objects.requireNonNull(attrs);
77        return FileVisitResult.CONTINUE;
78    }
79
80    /**
81     * Invoked for a file that could not be visited.
82     *
83     * <p> Unless overridden, this method re-throws the I/O exception that prevented
84     * the file from being visited.
85     */
86    @Override
87    public FileVisitResult visitFileFailed(T file, IOException exc)
88        throws IOException
89    {
90        Objects.requireNonNull(file);
91        throw exc;
92    }
93
94    /**
95     * Invoked for a directory after entries in the directory, and all of their
96     * descendants, have been visited.
97     *
98     * <p> Unless overridden, this method returns {@link FileVisitResult#CONTINUE
99     * CONTINUE} if the directory iteration completes without an I/O exception;
100     * otherwise this method re-throws the I/O exception that caused the iteration
101     * of the directory to terminate prematurely.
102     */
103    @Override
104    public FileVisitResult postVisitDirectory(T dir, IOException exc)
105        throws IOException
106    {
107        Objects.requireNonNull(dir);
108        if (exc != null)
109            throw exc;
110        return FileVisitResult.CONTINUE;
111    }
112}
113