1 /*
   2  * Copyright (c) 2005, 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 
  31 /*
  32  * Represents a key to a specific file on Solaris or Linux
  33  */
  34 public class FileKey {
  35 
  36     private long st_dev;    // ID of device
  37     private long st_ino;    // Inode number
  38 
  39     private FileKey() { }
  40 
  41     public static FileKey create(FileDescriptor fd) {
  42         FileKey fk = new FileKey();
  43         try {
  44             fk.init(fd);
  45         } catch (IOException ioe) {
  46             throw new Error(ioe);
  47         }
  48         return fk;
  49     }
  50 
  51     public int hashCode() {
  52         return (int)(st_dev ^ (st_dev >>> 32)) +
  53                (int)(st_ino ^ (st_ino >>> 32));
  54     }
  55 
  56     public boolean equals(Object obj) {
  57         if (obj == this)
  58             return true;
  59         if (!(obj instanceof FileKey))
  60             return false;
  61         FileKey other = (FileKey)obj;
  62         if ((this.st_dev != other.st_dev) ||
  63             (this.st_ino != other.st_ino)) {
  64             return false;
  65         }
  66         return true;
  67     }
  68 
  69     private native void init(FileDescriptor fd) throws IOException;
  70     private static native void initIDs();
  71 
  72     static {
  73         initIDs();
  74     }
  75 }