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      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 }
     81