1 /* ReflectUtil.java - JSR 166 reflection hooks 2 Copyright (C) 2006 Free Software Foundation 3 4 This file is part of GNU Classpath. 5 6 GNU Classpath is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 2, or (at your option) 9 any later version. 10 11 GNU Classpath is distributed in the hope that it will be useful, but 12 WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with GNU Classpath; see the file COPYING. If not, write to the 18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19 02110-1301 USA. 20 21 Linking this library statically or dynamically with other modules is 22 making a combined work based on this library. Thus, the terms and 23 conditions of the GNU General Public License cover the whole 24 combination. 25 26 As a special exception, the copyright holders of this library give you 27 permission to link this library with independent modules to produce an 28 executable, regardless of the license terms of these independent 29 modules, and to copy and distribute the resulting executable under 30 terms of your choice, provided that you also meet, for each linked 31 independent module, the terms and conditions of the license of that 32 module. An independent module is a module which is not derived from 33 or based on this library. If you modify this library, you may extend 34 this exception to your version of the library, but you are not 35 obligated to do so. If you do not wish to do so, delete this 36 exception statement from your version. */ 37 38 package sun.reflect.misc; 39 40 import java.lang.reflect.Modifier; 41 42 public class ReflectUtil 43 { 44 // We use this inaccessible inner class as an argument type 45 // in verifyMemberAccess. All current users of this method 46 // in the JSR 166 RI pass 'null' for this argument, and 47 // consequently we don't know what it means. Using a funny 48 // type like this for the argument means that if the RI changes, 49 // we will see a compilation error. 50 private static class MustBeNull 51 { 52 } 53 54 /** 55 * Check if the current thread is allowed to access the package of 56 * the declaringClass. 57 * 58 * @param declaringClass class name to check access to 59 * @throws SecurityException if permission is denied 60 * @throws NullPointerException if declaringClass is null 61 */ checkPackageAccess(Class declaringClass)62 public static void checkPackageAccess(Class declaringClass) 63 { 64 SecurityManager sm; 65 if ((sm = System.getSecurityManager()) != null) 66 { 67 while (declaringClass.isArray()) 68 declaringClass = declaringClass.getComponentType(); 69 String name = declaringClass.getName(); 70 int i = name.lastIndexOf('.'); 71 if (i != -1) // if declaringClass is a member of a package 72 { 73 name = name.substring(0, i); 74 sm.checkPackageAccess(name); 75 } 76 } 77 } 78 79 /** 80 * Perform access checks on a member of a class. This API is 81 * derived from the public domain code in the JSR 166 reference 82 * implementation. 83 * @param caller the class requesting access to the member 84 * @param declarer the declaring class of the member 85 * @param ignored unknown parameter; always null 86 * @param modifiers the modifiers on the member 87 * @return true if access is granted, false otherwise 88 */ ensureMemberAccess(Class caller, Class declarer, MustBeNull ignored, int modifiers)89 public static void ensureMemberAccess(Class caller, 90 Class declarer, 91 MustBeNull ignored, 92 int modifiers) 93 { 94 // Same class, always ok. 95 if (caller == declarer) 96 return; 97 // Public access is ok. 98 if ((modifiers & Modifier.PUBLIC) != 0) 99 return; 100 // Protected access and request comes from 101 // a subclass of the declarer -- ok. 102 if ((modifiers & Modifier.PROTECTED) != 0 103 && declarer.isAssignableFrom(caller)) 104 return; 105 // Package-private access, or protected access, 106 // and the packages are the same --ok. 107 if ((modifiers & Modifier.PRIVATE) == 0 108 && caller.getPackage() == declarer.getPackage()) 109 return; 110 // Otherwise, no. 111 throw new IllegalAccessError(); 112 } 113 } 114