1 /*
   2  * Copyright (c) 2007, 2016, 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.FileDescriptor;
  29 import java.io.IOException;
  30 import java.nio.channels.SelectableChannel;
  31 
  32 abstract class FileDispatcher extends NativeDispatcher {
  33 
  34     public static final int NO_LOCK = -1;       // Failed to lock
  35     public static final int LOCKED = 0;         // Obtained requested lock
  36     public static final int RET_EX_LOCK = 1;    // Obtained exclusive lock
  37     public static final int INTERRUPTED = 2;    // Request interrupted
  38 
  39     abstract int force(FileDescriptor fd, boolean metaData) throws IOException;
  40 
  41     abstract int truncate(FileDescriptor fd, long size) throws IOException;
  42 
  43     abstract int allocate(FileDescriptor fd, long size) throws IOException;
  44 
  45     abstract long size(FileDescriptor fd) throws IOException;
  46 
  47     abstract int lock(FileDescriptor fd, boolean blocking, long pos, long size,
  48                        boolean shared) throws IOException;
  49 
  50     abstract void release(FileDescriptor fd, long pos, long size)
  51         throws IOException;
  52 
  53     /**
  54      * Returns a dup of fd if a file descriptor is required for
  55      * memory-mapping operations, otherwise returns an invalid
  56      * FileDescriptor (meaning a newly allocated FileDescriptor)
  57      */
  58     abstract FileDescriptor duplicateForMapping(FileDescriptor fd)
  59         throws IOException;
  60 
  61     abstract boolean canTransferToDirectly(SelectableChannel sc);
  62 
  63     abstract boolean transferToDirectlyNeedsPositionLock();
  64 }