1 /*
   2  * Copyright (c) 2019, 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 jdk.internal.misc;
  27 
  28 import java.lang.invoke.MethodHandle;
  29 import java.lang.invoke.MethodHandles;
  30 import java.lang.invoke.MethodHandles.Lookup;
  31 import java.lang.invoke.MethodType;
  32 import java.nio.channels.FileChannel.MapMode;
  33 import java.security.AccessController;
  34 import java.security.PrivilegedExceptionAction;
  35 
  36 /**
  37  * JDK-specific map modes implemented in java.base.
  38  */
  39 public class ExtendedMapMode {
  40 
  41     static final MethodHandle MAP_MODE_CONSTRUCTOR;
  42     static {
  43         try {
  44             PrivilegedExceptionAction<Lookup> pae = () ->
  45                 MethodHandles.privateLookupIn(MapMode.class, MethodHandles.lookup());
  46             Lookup lookup = AccessController.doPrivileged(pae);
  47             var methodType = MethodType.methodType(void.class, String.class);
  48             MAP_MODE_CONSTRUCTOR = lookup.findConstructor(MapMode.class, methodType);
  49         } catch (Exception e) {
  50             throw new InternalError(e);
  51         }
  52     }
  53 
  54     public static final MapMode READ_ONLY_SYNC = newMapMode("READ_ONLY_SYNC");
  55 
  56     public static final MapMode READ_WRITE_SYNC = newMapMode("READ_WRITE_SYNC");
  57 
  58     private static MapMode newMapMode(String name) {
  59         try {
  60             return (MapMode) MAP_MODE_CONSTRUCTOR.invoke(name);
  61         } catch (Throwable e) {
  62             throw new InternalError(e);
  63         }
  64     }
  65 
  66     private ExtendedMapMode() { }
  67 }