/*
 * Copyright 2008-2009 Sun Microsystems, Inc.  All Rights Reserved.
 *
 * 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 Sun Microsystems 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
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * 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 system
        FileStore store = file.getFileStore();
        if (!store.supportsFileAttributeView("xattr")) {
            System.err.format("UserDefinedFileAttributeView not supported on %s\n", store);
            System.exit(-1);

        }
        UserDefinedFileAttributeView view = file.
            getFileAttributeView(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();
    }
 }