1 /*

     2  * Copyright (c) 2008, 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.

     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 

    24 import java.nio.file.*;

    25 import java.nio.file.attribute.*;

    26 import java.io.IOException;

    27 import java.util.*;

    28 

    29 /**

    30  * Invokes Files.walkFileTree to traverse a file tree and prints

    31  * each of the directories and files. The -follow option causes symbolic

    32  * links to be followed and the -printCycles option will print links

    33  * where the target of the link is an ancestor directory.

    34  */

    35 

    36 public class PrintFileTree {

    37 

    38     public static void main(String[] args) throws Exception {

    39         boolean followLinks = false;

    40         boolean printCycles = false;

    41         int i = 0;

    42         while (i < (args.length-1)) {

    43             switch (args[i]) {

    44                 case "-follow"      : followLinks = true; break;

    45                 case "-printCycles" : printCycles = true;  break;

    46                 default:

    47                     throw new RuntimeException(args[i] + " not recognized");

    48             }

    49             i++;

    50         }

    51         Path dir = Paths.get(args[i]);

    52 

    53         Set<FileVisitOption> options = new HashSet<FileVisitOption>();

    54         if (followLinks)

    55             options.add(FileVisitOption.FOLLOW_LINKS);

    56 

    57         final boolean follow = followLinks;

    58         final boolean reportCycles = printCycles;

    59         Files.walkFileTree(dir, options, Integer.MAX_VALUE, new FileVisitor<Path>() {

    60             @Override

    61             public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs) {

    62                 System.out.println(dir);

    63                 return FileVisitResult.CONTINUE;

    64             }

    65             @Override

    66             public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) {

    67                 System.out.println(file);

    68                 return FileVisitResult.CONTINUE;

    69             }

    70             @Override

    71             public FileVisitResult postVisitDirectory(Path dir, IOException exc)

    72                 throws IOException

    73             {

    74                 if (exc != null)

    75                     throw exc;

    76                 return FileVisitResult.CONTINUE;

    77             }

    78             @Override

    79             public FileVisitResult visitFileFailed(Path file, IOException exc)

    80                 throws IOException

    81             {

    82                 if (follow && (exc instanceof FileSystemLoopException)) {

    83                     if (reportCycles)

    84                         System.out.println(file);

    85                     return FileVisitResult.CONTINUE;

    86                 } else {

    87                     throw exc;

    88                 }

    89             }

    90         });

    91     }

    92 }