1 /*

     2  * Copyright (c) 2000, 2010, 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 /* @test

    25  * @summary Test read method of FileChannel

    26  */

    27 

    28 import java.io.*;

    29 import java.nio.ByteBuffer;

    30 import java.nio.CharBuffer;

    31 import java.nio.channels.*;

    32 import java.nio.channels.FileChannel;

    33 import java.util.Random;

    34 

    35 

    36 /**

    37  * Testing FileChannel's mapping capabilities.

    38  */

    39 

    40 public class Read {

    41 

    42     private static PrintStream err = System.err;

    43 

    44     private static Random generator = new Random();

    45 

    46     private static int CHARS_PER_LINE = File.separatorChar == '/' ? 5 : 6;

    47 

    48     private static File blah;

    49 

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

    51         StringBuffer sb = new StringBuffer();

    52         sb.setLength(4);

    53 

    54         blah = File.createTempFile("blah", null);

    55         blah.deleteOnExit();

    56         initTestFile(blah);

    57 

    58         FileInputStream fis = new FileInputStream(blah);

    59         FileChannel c = fis.getChannel();

    60 

    61         for (int x=0; x<1000; x++) {

    62             long offset = x * CHARS_PER_LINE;

    63             long expectedResult = offset / CHARS_PER_LINE;

    64             offset = expectedResult * CHARS_PER_LINE;

    65             ByteBuffer bleck = ByteBuffer.allocateDirect(CHARS_PER_LINE);

    66 

    67             c.read(bleck);

    68 

    69             for (int i=0; i<4; i++) {

    70                 byte aByte = bleck.get(i);

    71                 sb.setCharAt(i, (char)aByte);

    72             }

    73             int result = Integer.parseInt(sb.toString());

    74             if (result != expectedResult) {

    75                 err.println("I expected "+expectedResult);

    76                 err.println("I got "+ result);

    77                 throw new Exception("Read test failed");

    78             }

    79         }

    80 

    81         c.close();

    82         fis.close();

    83         blah.delete();

    84     }

    85 

    86     /**

    87      * Creates file blah:

    88      * 0000

    89      * 0001

    90      * 0002

    91      * 0003

    92      * .

    93      * .

    94      * .

    95      * 3999

    96      *

    97      * Blah extends beyond a single page of memory so that the

    98      * ability to index into a file of multiple pages is tested.

    99      */

   100     private static void initTestFile(File blah) throws Exception {

   101         FileOutputStream fos = new FileOutputStream(blah);

   102         BufferedWriter awriter

   103             = new BufferedWriter(new OutputStreamWriter(fos, "8859_1"));

   104 

   105         for(int i=0; i<4000; i++) {

   106             String number = new Integer(i).toString();

   107             for (int h=0; h<4-number.length(); h++)

   108                 awriter.write("0");

   109             awriter.write(""+i);

   110             awriter.newLine();

   111         }

   112        awriter.flush();

   113        awriter.close();

   114     }

   115 }