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 }