SkipSiblings.java revision 3471:236e3f2d0a6b 
1/*
2 * Copyright (c) 2008, 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.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24import java.nio.file.*;
25import java.nio.file.attribute.*;
26import java.io.IOException;
27import java.util.*;
28
29/**
30 * Unit test for Files.walkFileTree to test SKIP_SIBLINGS return value.
31 */
32
33public class SkipSiblings {
34
35    static final Random rand = new Random();
36    static final Set<Path> skipped = new HashSet<Path>();
37
38    // check if this path's directory has been skipped
39    static void check(Path path) {
40        if (skipped.contains(path.getParent()))
41            throw new RuntimeException(path + " should not have been visited");
42    }
43
44    // indicates if the siblings of this path should be skipped
45    static boolean skip(Path path) {
46        Path parent = path.getParent();
47        if (parent != null && rand.nextBoolean()) {
48            skipped.add(parent);
49            return true;
50        }
51        return false;
52    }
53
54    public static void main(String[] args) throws Exception {
55        Path dir = Paths.get(args[0]);
56
57        Files.walkFileTree(dir, new SimpleFileVisitor<Path>() {
58            @Override
59            public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs) {
60                check(dir);
61                if (skip(dir))
62                    return FileVisitResult.SKIP_SIBLINGS;
63                return FileVisitResult.CONTINUE;
64            }
65            @Override
66            public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) {
67                check(file);
68                if (skip(file))
69                    return FileVisitResult.SKIP_SIBLINGS;
70                return FileVisitResult.CONTINUE;
71            }
72            @Override
73            public FileVisitResult postVisitDirectory(Path dir, IOException x) {
74                if (x != null)
75                    throw new RuntimeException(x);
76                check(dir);
77                return FileVisitResult.CONTINUE;
78            }
79        });
80    }
81}
82