1 /*
   2  * Copyright (c) 2001, 2009, 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 import java.io.IOException;
  29 import java.nio.channels.*;
  30 
  31 public class FileLockImpl
  32     extends FileLock
  33 {
  34     private volatile boolean invalid;
  35 
  36     FileLockImpl(FileChannel channel, long position, long size, boolean shared)
  37     {
  38         super(channel, position, size, shared);
  39     }
  40 
  41     FileLockImpl(AsynchronousFileChannel channel, long position, long size, boolean shared)
  42     {
  43         super(channel, position, size, shared);
  44     }
  45 
  46     public boolean isValid() {
  47         return !invalid;
  48     }
  49 
  50     void invalidate() {
  51         assert Thread.holdsLock(this);
  52         invalid = true;
  53     }
  54 
  55     public synchronized void release() throws IOException {
  56         Channel ch = acquiredBy();
  57         if (!ch.isOpen())
  58             throw new ClosedChannelException();
  59         if (isValid()) {
  60             if (ch instanceof FileChannelImpl)
  61                 ((FileChannelImpl)ch).release(this);
  62             else if (ch instanceof AsynchronousFileChannelImpl)
  63                 ((AsynchronousFileChannelImpl)ch).release(this);
  64             else throw new AssertionError();
  65             invalidate();
  66         }
  67     }
  68 }