1 /*
   2  * Copyright (c) 2002, 2013, 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.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package sun.nio.ch;
  27 
  28 
  29 // Signalling operations on native threads
  30 //
  31 // On some operating systems (e.g., Linux), closing a channel while another
  32 // thread is blocked in an I/O operation upon that channel does not cause that
  33 // thread to be released.  This class provides access to the native threads
  34 // upon which Java threads are built, and defines a simple signal mechanism
  35 // that can be used to release a native thread from a blocking I/O operation.
  36 // On systems that do not require this type of signalling, the current() method
  37 // always returns -1 and the signal(long) method has no effect.
  38 
  39 
  40 public class NativeThread {
  41 
  42     // Returns an opaque token representing the native thread underlying the
  43     // invoking Java thread.  On systems that do not require signalling, this
  44     // method always returns -1.
  45     //
  46     public static native long current();
  47 
  48     // Signals the given native thread so as to release it from a blocking I/O
  49     // operation.  On systems that do not require signalling, this method has
  50     // no effect.
  51     //
  52     public static native void signal(long nt);
  53 
  54     private static native void init();
  55 
  56     static {
  57         IOUtil.load();
  58         init();
  59     }
  60 
  61 }