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
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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 }