--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/sun/nio/ch/AsynchronousFileChannelImpl.java	Sun Feb 15 12:25:54 2009 +0000
@@ -0,0 +1,164 @@
+/*
+ * Copyright 2008-2009 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package sun.nio.ch;
+
+import java.nio.channels.*;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.locks.*;
+import java.io.FileDescriptor;
+import java.io.IOException;
+
+/**
+ * Base implementation of AsynchronousFileChannel.
+ */
+
+abstract class AsynchronousFileChannelImpl
+    extends AsynchronousFileChannel
+{
+    // close support
+    protected final ReadWriteLock closeLock = new ReentrantReadWriteLock();
+    protected volatile boolean closed;
+
+    // file descriptor
+    protected final FileDescriptor fdObj;
+
+    // indicates if open for reading/writing
+    protected final boolean reading;
+    protected final boolean writing;
+
+    // associated Executor
+    protected final ExecutorService executor;
+
+    protected AsynchronousFileChannelImpl(FileDescriptor fdObj,
+                                          boolean reading,
+                                          boolean writing,
+                                          ExecutorService executor)
+    {
+        this.fdObj = fdObj;
+        this.reading = reading;
+        this.writing = writing;
+        this.executor = executor;
+    }
+
+    final ExecutorService executor() {
+        return executor;
+    }
+
+    @Override
+    public final boolean isOpen() {
+        return !closed;
+    }
+
+    /**
+     * Marks the beginning of an I/O operation.
+     *
+     * @throws  ClosedChannelException  If channel is closed
+     */
+    protected final void begin() throws IOException {
+        closeLock.readLock().lock();
+        if (closed)
+            throw new ClosedChannelException();
+    }
+
+    /**
+     * Marks the end of an I/O operation.
+     */
+    protected final void end() {
+        closeLock.readLock().unlock();
+    }
+
+    /**
+     * Marks end of I/O operation
+     */
+    protected final void end(boolean completed) throws IOException {
+        end();
+        if (!completed && !isOpen())
+            throw new AsynchronousCloseException();
+    }
+
+    // -- file locking --
+
+    private volatile FileLockTable fileLockTable;
+
+    final void ensureFileLockTableInitialized() throws IOException {
+        if (fileLockTable == null) {
+            synchronized (this) {
+                if (fileLockTable == null) {
+                    fileLockTable = FileLockTable.newSharedFileLockTable(this, fdObj);
+                }
+            }
+        }
+    }
+
+    final void invalidateAllLocks() {
+        if (fileLockTable != null) {
+            try {
+                fileLockTable.removeAll( new FileLockTable.Releaser() {
+                    public void release(FileLock fl) {
+                        ((FileLockImpl)fl).invalidate();
+                    }
+                });
+            } catch (IOException e) {
+                throw new AssertionError(e);
+            }
+        }
+    }
+
+    /**
+     * Adds region to lock table
+     */
+    protected final FileLockImpl addToFileLockTable(long position, long size, boolean shared) {
+        final FileLockImpl fli;
+        try {
+            // like begin() but returns null instead of exception
+            closeLock.readLock().lock();
+            if (closed)
+                return null;
+
+            try {
+                ensureFileLockTableInitialized();
+            } catch (IOException x) {
+                // should not happen
+                throw new AssertionError(x);
+            }
+            fli = new FileLockImpl(this, position, size, shared);
+            // may throw OverlappedFileLockException
+            fileLockTable.add(fli);
+        } finally {
+            end();
+        }
+        return fli;
+    }
+
+    protected final void removeFromFileLockTable(FileLockImpl fli) {
+        fileLockTable.remove(fli);
+    }
+
+    /**
+     * Invoked by FileLockImpl to release lock acquired by this channel.
+     */
+    abstract void release(FileLockImpl fli) throws IOException;
+}