001 /* AllPermission.java -- Permission to do anything 002 Copyright (C) 1998, 2001, 2002, 2004, 2005 Free Software Foundation, Inc. 003 004 This file is part of GNU Classpath. 005 006 GNU Classpath is free software; you can redistribute it and/or modify 007 it under the terms of the GNU General Public License as published by 008 the Free Software Foundation; either version 2, or (at your option) 009 any later version. 010 011 GNU Classpath is distributed in the hope that it will be useful, but 012 WITHOUT ANY WARRANTY; without even the implied warranty of 013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 014 General Public License for more details. 015 016 You should have received a copy of the GNU General Public License 017 along with GNU Classpath; see the file COPYING. If not, write to the 018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 019 02110-1301 USA. 020 021 Linking this library statically or dynamically with other modules is 022 making a combined work based on this library. Thus, the terms and 023 conditions of the GNU General Public License cover the whole 024 combination. 025 026 As a special exception, the copyright holders of this library give you 027 permission to link this library with independent modules to produce an 028 executable, regardless of the license terms of these independent 029 modules, and to copy and distribute the resulting executable under 030 terms of your choice, provided that you also meet, for each linked 031 independent module, the terms and conditions of the license of that 032 module. An independent module is a module which is not derived from 033 or based on this library. If you modify this library, you may extend 034 this exception to your version of the library, but you are not 035 obligated to do so. If you do not wish to do so, delete this 036 exception statement from your version. */ 037 038 039 package java.security; 040 041 import gnu.java.util.EmptyEnumeration; 042 043 import java.util.Collections; 044 import java.util.Enumeration; 045 046 /** 047 * This class is a permission that implies all other permissions. Granting 048 * this permission effectively grants all others. Extreme caution should 049 * be exercised in granting this permission. 050 * 051 * @author Aaron M. Renn (arenn@urbanophile.com) 052 * @author Eric Blake (ebb9@email.byu.edu) 053 * @see AccessController 054 * @see Permissions 055 * @see SecurityManager 056 * @since 1.1 057 * @status updated to 1.4 058 */ 059 public final class AllPermission extends Permission 060 { 061 /** 062 * Compatible with JDK 1.1+. 063 */ 064 private static final long serialVersionUID = -2916474571451318075L; 065 066 /** 067 * Create a new AllPermission object. 068 */ 069 public AllPermission() 070 { 071 super("*"); 072 } 073 074 /** 075 * Create a new AllPermission object. The parameters are ignored, as all 076 * permission implies ALL PERMISSION. 077 * 078 * @param name ignored 079 * @param actions ignored 080 */ 081 public AllPermission(String name, String actions) 082 { 083 super("*"); 084 } 085 086 /** 087 * This method always returns <code>true</code> to indicate that this 088 * permission always implies that any other permission is also granted. 089 * 090 * @param perm ignored 091 * @return true, the permission is implied 092 */ 093 public boolean implies(Permission perm) 094 { 095 return true; 096 } 097 098 /** 099 * Checks an object for equality. All AllPermissions are equal. 100 * 101 * @param obj the <code>Object</code> to test for equality 102 */ 103 public boolean equals(Object obj) 104 { 105 return obj instanceof AllPermission; 106 } 107 108 /** 109 * This method returns a hash code for this object. This returns 1. 110 * 111 * @return a hash value for this object 112 */ 113 public int hashCode() 114 { 115 return 1; 116 } 117 118 /** 119 * This method returns the list of actions associated with this object. 120 * This will always be the empty string ("") for this class. 121 * 122 * @return the action list 123 */ 124 public String getActions() 125 { 126 return ""; 127 } 128 129 /** 130 * Returns a PermissionCollection which can hold AllPermission. 131 * 132 * @return a permission collection 133 */ 134 public PermissionCollection newPermissionCollection() 135 { 136 return new AllPermissionCollection(); 137 } 138 139 /** 140 * Implements AllPermission.newPermissionCollection, and obeys serialization 141 * of JDK. 142 * 143 * @author Eric Blake (ebb9@email.byu.edu) 144 */ 145 private static final class AllPermissionCollection extends PermissionCollection 146 { 147 /** 148 * Compatible with JDK 1.1+. 149 */ 150 private static final long serialVersionUID = -4023755556366636806L; 151 152 /** 153 * Whether an AllPermission has been added to the collection. 154 * 155 * @serial if all permission is in the collection yet 156 */ 157 private boolean all_allowed; 158 159 /** 160 * Add an AllPermission. 161 * 162 * @param perm the permission to add 163 * @throws IllegalArgumentException if perm is not an AllPermission 164 * @throws SecurityException if the collection is read-only 165 */ 166 public void add(Permission perm) 167 { 168 if (isReadOnly()) 169 throw new SecurityException(); 170 if (! (perm instanceof AllPermission)) 171 throw new IllegalArgumentException(); 172 all_allowed = true; 173 } 174 175 /** 176 * Returns true if this collection implies a permission. 177 * 178 * @param perm the permission to check 179 * @return true if this collection contains an AllPermission 180 */ 181 public boolean implies(Permission perm) 182 { 183 return all_allowed; 184 } 185 186 /** 187 * Returns an enumeration of the elements in the collection. 188 * 189 * @return the elements in the collection 190 */ 191 public Enumeration elements() 192 { 193 return all_allowed 194 ? Collections.enumeration(Collections.singleton(new AllPermission())) 195 : EmptyEnumeration.getInstance(); 196 } 197 } // class AllPermissionCollection 198 } // class AllPermission