1 /*
   2  * Copyright (c) 2000, 2013, 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.*;
  29 
  30 /**
  31  * Allows different platforms to call different native methods
  32  * for read and write operations.
  33  */
  34 
  35 abstract class NativeDispatcher
  36 {
  37 
  38     abstract int read(FileDescriptor fd, long address, int len)
  39         throws IOException;
  40 
  41     /**
  42      * Returns {@code true} if pread/pwrite needs to be synchronized with
  43      * position sensitive methods.
  44      */
  45     boolean needsPositionLock() {
  46         return false;
  47     }
  48 
  49     int pread(FileDescriptor fd, long address, int len, long position)
  50         throws IOException
  51     {
  52         throw new IOException("Operation Unsupported");
  53     }
  54 
  55     abstract long readv(FileDescriptor fd, long address, int len)
  56         throws IOException;
  57 
  58     abstract int write(FileDescriptor fd, long address, int len)
  59         throws IOException;
  60 
  61     int pwrite(FileDescriptor fd, long address, int len, long position)
  62         throws IOException
  63     {
  64         throw new IOException("Operation Unsupported");
  65     }
  66 
  67     abstract long writev(FileDescriptor fd, long address, int len)
  68         throws IOException;
  69 
  70     abstract void close(FileDescriptor fd) throws IOException;
  71 
  72     // Prepare the given fd for closing by duping it to a known internal fd
  73     // that's already closed.  This is necessary on some operating systems
  74     // (Solaris and Linux) to prevent fd recycling.
  75     //
  76     void preClose(FileDescriptor fd) throws IOException {
  77         // Do nothing by default; this is only needed on Unix
  78     }
  79 
  80 }