1 /*
   2  * Copyright (c) 2001, 2018, 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.reflect;
  27 
  28 import java.lang.reflect.Field;
  29 import java.lang.reflect.Modifier;
  30 import java.security.AccessController;
  31 import java.util.Set;
  32 
  33 import jdk.internal.misc.Unsafe;
  34 
  35 /** Base class for jdk.internal.misc.Unsafe-based FieldAccessors for static
  36     fields. The observation is that there are only nine types of
  37     fields from the standpoint of reflection code: the eight primitive
  38     types and Object. Using class Unsafe instead of generated
  39     bytecodes saves memory and loading time for the
  40     dynamically-generated FieldAccessors. */
  41 
  42 abstract class UnsafeStaticFieldAccessorImpl extends UnsafeFieldAccessorImpl {
  43     static {
  44         Reflection.registerFieldsToFilter(UnsafeStaticFieldAccessorImpl.class,
  45                                           Set.of("base"));
  46     }
  47 
  48     protected final Object base; // base
  49 
  50     UnsafeStaticFieldAccessorImpl(Field field) {
  51         super(field);
  52         base = unsafe.staticFieldBase(field);
  53     }
  54 }