/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

import java.nio.file.*;

import java.nio.file.attribute.*;

import java.io.IOException;

import java.util.*;

/**

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

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

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

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

 */

public class PrintFileTree {

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

        boolean followLinks = false;

        boolean printCycles = false;

        int i = 0;

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

            switch (args[i]) {

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

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

                default:

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

            }

            i++;

        }

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

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

        if (followLinks)

            options.add(FileVisitOption.FOLLOW_LINKS);

        final boolean follow = followLinks;

        final boolean reportCycles = printCycles;

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

            @Override

            public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs) {

                System.out.println(dir);

                return FileVisitResult.CONTINUE;

            }

            @Override

            public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) {

                System.out.println(file);

                return FileVisitResult.CONTINUE;

            }

            @Override

            public FileVisitResult postVisitDirectory(Path dir, IOException exc)

                throws IOException

            {

                if (exc != null)

                    throw exc;

                return FileVisitResult.CONTINUE;

            }

            @Override

            public FileVisitResult visitFileFailed(Path file, IOException exc)

                throws IOException

            {

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

                    if (reportCycles)

                        System.out.println(file);

                    return FileVisitResult.CONTINUE;

                } else {

                    throw exc;

                }

            }

        });

    }

}