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      1 /*
      2  * Copyright (c) 2008, 2011, Oracle and/or its affiliates. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  *
      8  *   - Redistributions of source code must retain the above copyright
      9  *     notice, this list of conditions and the following disclaimer.
     10  *
     11  *   - Redistributions in binary form must reproduce the above copyright
     12  *     notice, this list of conditions and the following disclaimer in the
     13  *     documentation and/or other materials provided with the distribution.
     14  *
     15  *   - Neither the name of Oracle nor the names of its
     16  *     contributors may be used to endorse or promote products derived
     17  *     from this software without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
     20  * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
     21  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
     23  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     24  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     25  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     26  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
     27  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
     28  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
     29  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 /*
     33  * This source code is provided to illustrate the usage of a given feature
     34  * or technique and has been deliberately simplified. Additional steps
     35  * required for a production-quality application, such as security checks,
     36  * input validation and proper error handling, might not be present in
     37  * this sample code.
     38  */
     39 
     40 
     41 import java.nio.ByteBuffer;
     42 import java.nio.charset.Charset;
     43 import java.nio.file.*;
     44 import java.nio.file.attribute.*;
     45 import java.io.IOException;
     46 
     47 /**
     48  * Example code to list/set/get/delete the user-defined attributes of a file.
     49  */
     50 
     51 public class Xdd {
     52 
     53     static void usage() {
     54         System.out.println("Usage: java Xdd <file>");
     55         System.out.println("       java Xdd -set <name>=<value> <file>");
     56         System.out.println("       java Xdd -get <name> <file>");
     57         System.out.println("       java Xdd -del <name> <file>");
     58         System.exit(-1);
     59     }
     60 
     61     public static void main(String[] args) throws IOException {
     62         // one or three parameters
     63         if (args.length != 1 && args.length != 3)
     64             usage();
     65 
     66         Path file = (args.length == 1) ?
     67             Paths.get(args[0]) : Paths.get(args[2]);
     68 
     69         // check that user defined attributes are supported by the file store
     70         FileStore store = Files.getFileStore(file);
     71         if (!store.supportsFileAttributeView(UserDefinedFileAttributeView.class)) {
     72             System.err.format("UserDefinedFileAttributeView not supported on %s\n", store);
     73             System.exit(-1);
     74 
     75         }
     76         UserDefinedFileAttributeView view =
     77             Files.getFileAttributeView(file, UserDefinedFileAttributeView.class);
     78 
     79         // list user defined attributes
     80         if (args.length == 1) {
     81             System.out.println("    Size  Name");
     82             System.out.println("--------  --------------------------------------");
     83             for (String name: view.list()) {
     84                 System.out.format("%8d  %s\n", view.size(name), name);
     85             }
     86             return;
     87         }
     88 
     89         // Add/replace a file's user defined attribute
     90         if (args[0].equals("-set")) {
     91             // name=value
     92             String[] s = args[1].split("=");
     93             if (s.length != 2)
     94                 usage();
     95             String name = s[0];
     96             String value = s[1];
     97             view.write(name, Charset.defaultCharset().encode(value));
     98             return;
     99         }
    100 
    101         // Print out the value of a file's user defined attribute
    102         if (args[0].equals("-get")) {
    103             String name = args[1];
    104             int size = view.size(name);
    105             ByteBuffer buf = ByteBuffer.allocateDirect(size);
    106             view.read(name, buf);
    107             buf.flip();
    108             System.out.println(Charset.defaultCharset().decode(buf).toString());
    109             return;
    110         }
    111 
    112         // Delete a file's user defined attribute
    113         if (args[0].equals("-del")) {
    114             view.delete(args[1]);
    115             return;
    116         }
    117 
    118         // option not recognized
    119         usage();
    120     }
    121  }
    122