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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 
FileLockImpl(FileChannel channel, long position, long size, boolean shared)36     FileLockImpl(FileChannel channel, long position, long size, boolean shared)
37     {
38         super(channel, position, size, shared);
39     }
40 
FileLockImpl(AsynchronousFileChannel channel, long position, long size, boolean shared)41     FileLockImpl(AsynchronousFileChannel channel, long position, long size, boolean shared)
42     {
43         super(channel, position, size, shared);
44     }
45 
isValid()46     public boolean isValid() {
47         return !invalid;
48     }
49 
invalidate()50     void invalidate() {
51         assert Thread.holdsLock(this);
52         invalid = true;
53     }
54 
release()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 }
69