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      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 valid = true;
     35 
     36     FileLockImpl(FileChannel channel, long position, long size, boolean shared)
     37     {
     38         super(channel, position, size, shared);
     39     }
     40 
     41     public boolean isValid() {
     42         return valid;
     43     }
     44 
     45     void invalidate() {
     46         assert Thread.holdsLock(this);
     47         valid = false;
     48     }
     49 
     50     public synchronized void release() throws IOException {
     51         Channel ch = acquiredBy();
     52         if (!ch.isOpen())
     53             throw new ClosedChannelException();
     54         if (valid) {
     55             if (ch instanceof FileChannelImpl)
     56                 ((FileChannelImpl)ch).release(this);
     57             else throw new AssertionError();
     58             valid = false;
     59         }
     60     }
     61 }
     62