1 /*
   2  * Copyright (c) 2008, 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  * @bug 6448457
  26  * @summary Test Channels.newOutputStream returns OutputStream that handles
  27  *     short writes from the underlying channel
  28  * @key randomness
  29  */
  30 
  31 import java.io.OutputStream;
  32 import java.io.IOException;
  33 import java.nio.ByteBuffer;
  34 import java.nio.channels.*;
  35 import java.util.Random;
  36 
  37 public class ShortWrite {
  38 
  39     static Random rand = new Random();
  40     static int bytesWritten = 0;
  41 
  42     public static void main(String[] args) throws IOException {
  43 
  44         WritableByteChannel wbc = new WritableByteChannel() {
  45             public int write(ByteBuffer src) {
  46                 int rem = src.remaining();
  47                 if (rem > 0) {
  48                     // short write
  49                     int n = rand.nextInt(rem) + 1;
  50                     src.position(src.position() + n);
  51                     bytesWritten += n;
  52                     return n;
  53                 } else {
  54                     return 0;
  55                 }
  56             }
  57             public void close() throws IOException {
  58                 throw new RuntimeException("not implemented");
  59             }
  60             public boolean isOpen() {
  61                 throw new RuntimeException("not implemented");
  62             }
  63         };
  64 
  65         // wrap Channel with OutputStream
  66         OutputStream out = Channels.newOutputStream(wbc);
  67 
  68 
  69         // write 100, 99, 98, ... 1
  70         // and check that the expected number of bytes is written
  71         int expected = 0;
  72         byte[] buf = new byte[100];
  73         for (int i=0; i<buf.length; i++) {
  74             int len = buf.length-i;
  75             out.write(buf, i, len);
  76             expected += len;
  77         }
  78         System.out.format("Bytes written: %d, expected: %d\n", bytesWritten,
  79             expected);
  80         if (bytesWritten != expected)
  81             throw new RuntimeException("incorrect number of bytes written");
  82 
  83     }
  84 }