1 /*
   2  * Copyright (c) 2000, 2012, 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 utilities
  25  *
  26  */
  27 
  28 import java.io.*;
  29 import java.net.*;
  30 import java.nio.channels.*;
  31 import java.util.Random;
  32 
  33 
  34 public class TestUtil {
  35 
  36     // Test hosts used by the channels tests - change these when
  37     // executing in a different network.
  38     public static final String UNRESOLVABLE_HOST = "blah-blah.blah-blah.blah";
  39 
  40     private TestUtil() { }
  41 
  42     // Repeatedly try random ports until we bind to one.  You might be tempted
  43     // to do this:
  44     //
  45     //     ServerSocketChannel ssc = ServerSocketChannel.open();
  46     //     ssc.socket().bind(new InetSocketAddress(0));
  47     //     SocketAddress sa = ssc.socket().getLocalSocketAddress();
  48     //
  49     // but unfortunately it doesn't work on NT 4.0.
  50     //
  51     // Returns the bound port.
  52     //
  53     static int bind(ServerSocketChannel ssc) throws IOException {
  54         InetAddress lh = InetAddress.getLocalHost();
  55         Random r = new Random();
  56         for (;;) {
  57             int p = r.nextInt((1 << 16) - 1024) + 1024;
  58             InetSocketAddress isa = new InetSocketAddress(lh, p);
  59             try {
  60                 ssc.socket().bind(isa);
  61             } catch (IOException x) {
  62                 continue;
  63             }
  64             return p;
  65         }
  66     }
  67 
  68     // A more convenient form of bind(ServerSocketChannel) that returns a full
  69     // socket address.
  70     //
  71     static InetSocketAddress bindToRandomPort(ServerSocketChannel ssc)
  72         throws IOException
  73     {
  74         int p = bind(ssc);
  75         return new InetSocketAddress(InetAddress.getLocalHost(), p);
  76     }
  77 
  78     private static String osName = System.getProperty("os.name");
  79 
  80     static boolean onWindows() {
  81         return osName.startsWith("Windows");
  82     }
  83 }