/*

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 *   - Redistributions of source code must retain the above copyright

 *     notice, this list of conditions and the following disclaimer.

 *

 *   - Redistributions in binary form must reproduce the above copyright

 *     notice, this list of conditions and the following disclaimer in the

 *     documentation and/or other materials provided with the distribution.

 *

 *   - Neither the name of Oracle nor the names of its

 *     contributors may be used to endorse or promote products derived

 *     from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS

 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,

 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR

 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF

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 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

import java.nio.ByteBuffer;

import java.nio.charset.Charset;

import java.nio.file.*;

import java.nio.file.attribute.*;

import java.io.IOException;

/**

 * Example code to list/set/get/delete the user-defined attributes of a file.

 */

public class Xdd {

    static void usage() {

        System.out.println("Usage: java Xdd <file>");

        System.out.println("       java Xdd -set <name>=<value> <file>");

        System.out.println("       java Xdd -get <name> <file>");

        System.out.println("       java Xdd -del <name> <file>");

        System.exit(-1);

    }

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

        // one or three parameters

        if (args.length != 1 && args.length != 3)

            usage();

        Path file = (args.length == 1) ?

            Paths.get(args[0]) : Paths.get(args[2]);

        // check that user defined attributes are supported by the file store

        FileStore store = Files.getFileStore(file);

        if (!store.supportsFileAttributeView(UserDefinedFileAttributeView.class)) {

            System.err.format("UserDefinedFileAttributeView not supported on %s\n", store);

            System.exit(-1);

        }

        UserDefinedFileAttributeView view =

            Files.getFileAttributeView(file, UserDefinedFileAttributeView.class);

        // list user defined attributes

        if (args.length == 1) {

            System.out.println("    Size  Name");

            System.out.println("--------  --------------------------------------");

            for (String name: view.list()) {

                System.out.format("%8d  %s\n", view.size(name), name);

            }

            return;

        }

        // Add/replace a file's user defined attribute

        if (args[0].equals("-set")) {

            // name=value

            String[] s = args[1].split("=");

            if (s.length != 2)

                usage();

            String name = s[0];

            String value = s[1];

            view.write(name, Charset.defaultCharset().encode(value));

            return;

        }

        // Print out the value of a file's user defined attribute

        if (args[0].equals("-get")) {

            String name = args[1];

            int size = view.size(name);

            ByteBuffer buf = ByteBuffer.allocateDirect(size);

            view.read(name, buf);

            buf.flip();

            System.out.println(Charset.defaultCharset().decode(buf).toString());

            return;

        }

        // Delete a file's user defined attribute

        if (args[0].equals("-del")) {

            view.delete(args[1]);

            return;

        }

        // option not recognized

        usage();

    }

 }