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