ShortWrite.java revision 43:278e769f9123 
1/*
2 * Copyright 2008 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any 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 */
29
30import java.io.OutputStream;
31import java.io.IOException;
32import java.nio.ByteBuffer;
33import java.nio.channels.*;
34import java.util.Random;
35
36public class ShortWrite {
37
38    static Random rand = new Random();
39    static int bytesWritten = 0;
40
41    public static void main(String[] args) throws IOException {
42
43        WritableByteChannel wbc = new WritableByteChannel() {
44            public int write(ByteBuffer src) {
45                int rem = src.remaining();
46                if (rem > 0) {
47                    // short write
48                    int n = rand.nextInt(rem) + 1;
49                    src.position(src.position() + n);
50                    bytesWritten += n;
51                    return n;
52                } else {
53                    return 0;
54                }
55            }
56            public void close() throws IOException {
57                throw new RuntimeException("not implemented");
58            }
59            public boolean isOpen() {
60                throw new RuntimeException("not implemented");
61            }
62        };
63
64        // wrap Channel with OutputStream
65        OutputStream out = Channels.newOutputStream(wbc);
66
67
68        // write 100, 99, 98, ... 1
69        // and check that the expected number of bytes is written
70        int expected = 0;
71        byte[] buf = new byte[100];
72        for (int i=0; i<buf.length; i++) {
73            int len = buf.length-i;
74            out.write(buf, i, len);
75            expected += len;
76        }
77        System.out.format("Bytes written: %d, expected: %d\n", bytesWritten,
78            expected);
79        if (bytesWritten != expected)
80            throw new RuntimeException("incorrect number of bytes written");
81
82    }
83}
84