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| 1 | /* | ||
| 2 | * Copyright (c) 1997, 2006, 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 java.security; | ||
| 27 | |||
| 28 | import java.util.*; | ||
| 29 | |||
| 30 | /** | ||
| 31 | * Abstract class representing a collection of Permission objects. | ||
| 32 | * | ||
| 33 | * <p>With a PermissionCollection, you can: | ||
| 34 | * <UL> | ||
| 35 | * <LI> add a permission to the collection using the <code>add</code> method. | ||
| 36 | * <LI> check to see if a particular permission is implied in the | ||
| 37 | * collection, using the <code>implies</code> method. | ||
| 38 | * <LI> enumerate all the permissions, using the <code>elements</code> method. | ||
| 39 | * </UL> | ||
| 40 | * <P> | ||
| 41 | * | ||
| 42 | * <p>When it is desirable to group together a number of Permission objects | ||
| 43 | * of the same type, the <code>newPermissionCollection</code> method on that | ||
| 44 | * particular type of Permission object should first be called. The default | ||
| 45 | * behavior (from the Permission class) is to simply return null. | ||
| 46 | * Subclasses of class Permission override the method if they need to store | ||
| 47 | * their permissions in a particular PermissionCollection object in order | ||
| 48 | * to provide the correct semantics when the | ||
| 49 | * <code>PermissionCollection.implies</code> method is called. | ||
| 50 | * If a non-null value is returned, that PermissionCollection must be used. | ||
| 51 | * If null is returned, then the caller of <code>newPermissionCollection</code> | ||
| 52 | * is free to store permissions of the | ||
| 53 | * given type in any PermissionCollection they choose | ||
| 54 | * (one that uses a Hashtable, one that uses a Vector, etc). | ||
| 55 | * | ||
| 56 | * <p>The PermissionCollection returned by the | ||
| 57 | * <code>Permission.newPermissionCollection</code> | ||
| 58 | * method is a homogeneous collection, which stores only Permission objects | ||
| 59 | * for a given Permission type. A PermissionCollection may also be | ||
| 60 | * heterogeneous. For example, Permissions is a PermissionCollection | ||
| 61 | * subclass that represents a collection of PermissionCollections. | ||
| 62 | * That is, its members are each a homogeneous PermissionCollection. | ||
| 63 | * For example, a Permissions object might have a FilePermissionCollection | ||
| 64 | * for all the FilePermission objects, a SocketPermissionCollection for all the | ||
| 65 | * SocketPermission objects, and so on. Its <code>add</code> method adds a | ||
| 66 | * permission to the appropriate collection. | ||
| 67 | * | ||
| 68 | * <p>Whenever a permission is added to a heterogeneous PermissionCollection | ||
| 69 | * such as Permissions, and the PermissionCollection doesn't yet contain a | ||
| 70 | * PermissionCollection of the specified permission's type, the | ||
| 71 | * PermissionCollection should call | ||
| 72 | * the <code>newPermissionCollection</code> method on the permission's class | ||
| 73 | * to see if it requires a special PermissionCollection. If | ||
| 74 | * <code>newPermissionCollection</code> | ||
| 75 | * returns null, the PermissionCollection | ||
| 76 | * is free to store the permission in any type of PermissionCollection it | ||
| 77 | * desires (one using a Hashtable, one using a Vector, etc.). For example, | ||
| 78 | * the Permissions object uses a default PermissionCollection implementation | ||
| 79 | * that stores the permission objects in a Hashtable. | ||
| 80 | * | ||
| 81 | * <p> Subclass implementations of PermissionCollection should assume | ||
| 82 | * that they may be called simultaneously from multiple threads, | ||
| 83 | * and therefore should be synchronized properly. Furthermore, | ||
| 84 | * Enumerations returned via the <code>elements</code> method are | ||
| 85 | * not <em>fail-fast</em>. Modifications to a collection should not be | ||
| 86 | * performed while enumerating over that collection. | ||
| 87 | * | ||
| 88 | * @see Permission | ||
| 89 | * @see Permissions | ||
| 90 | * | ||
| 91 | * | ||
| 92 | * @author Roland Schemers | ||
| 93 | */ | ||
| 94 | |||
| 95 | public abstract class PermissionCollection implements java.io.Serializable { | ||
| 96 | |||
| 97 | private static final long serialVersionUID = -6727011328946861783L; | ||
| 98 | |||
| 99 | // when set, add will throw an exception. | ||
| 100 | private volatile boolean readOnly; | ||
| 101 | |||
| 102 | /** | ||
| 103 | * Adds a permission object to the current collection of permission objects. | ||
| 104 | * | ||
| 105 | * @param permission the Permission object to add. | ||
| 106 | * | ||
| 107 | * @exception SecurityException - if this PermissionCollection object | ||
| 108 | * has been marked readonly | ||
| 109 | * @exception IllegalArgumentException - if this PermissionCollection | ||
| 110 | * object is a homogeneous collection and the permission | ||
| 111 | * is not of the correct type. | ||
| 112 | */ | ||
| 113 | public abstract void add(Permission permission); | ||
| 114 | |||
| 115 | /** | ||
| 116 | * Checks to see if the specified permission is implied by | ||
| 117 | * the collection of Permission objects held in this PermissionCollection. | ||
| 118 | * | ||
| 119 | * @param permission the Permission object to compare. | ||
| 120 | * | ||
| 121 | * @return true if "permission" is implied by the permissions in | ||
| 122 | * the collection, false if not. | ||
| 123 | */ | ||
| 124 | public abstract boolean implies(Permission permission); | ||
| 125 | |||
| 126 | /** | ||
| 127 | * Returns an enumeration of all the Permission objects in the collection. | ||
| 128 | * | ||
| 129 | * @return an enumeration of all the Permissions. | ||
| 130 | */ | ||
| 131 | public abstract Enumeration<Permission> elements(); | ||
| 132 | |||
| 133 | /** | ||
| 134 | * Marks this PermissionCollection object as "readonly". After | ||
| 135 | * a PermissionCollection object | ||
| 136 | * is marked as readonly, no new Permission objects can be added to it | ||
| 137 | * using <code>add</code>. | ||
| 138 | */ | ||
| 139 | public void setReadOnly() { | ||
| 140 | readOnly = true; | ||
| 141 | } | ||
| 142 | |||
| 143 | /** | ||
| 144 | * Returns true if this PermissionCollection object is marked as readonly. | ||
| 145 | * If it is readonly, no new Permission objects can be added to it | ||
| 146 | * using <code>add</code>. | ||
| 147 | * | ||
| 148 | * <p>By default, the object is <i>not</i> readonly. It can be set to | ||
| 149 | * readonly by a call to <code>setReadOnly</code>. | ||
| 150 | * | ||
| 151 | * @return true if this PermissionCollection object is marked as readonly, | ||
| 152 | * false otherwise. | ||
| 153 | */ | ||
| 154 | public boolean isReadOnly() { | ||
| 155 | return readOnly; | ||
| 156 | } | ||
| 157 | |||
| 158 | /** | ||
| 159 | * Returns a string describing this PermissionCollection object, | ||
| 160 | * providing information about all the permissions it contains. | ||
| 161 | * The format is: | ||
| 162 | * <pre> | ||
| 163 | * super.toString() ( | ||
| 164 | * // enumerate all the Permission | ||
| 165 | * // objects and call toString() on them, | ||
| 166 | * // one per line.. | ||
| 167 | * )</pre> | ||
| 168 | * | ||
| 169 | * <code>super.toString</code> is a call to the <code>toString</code> | ||
| 170 | * method of this | ||
| 171 | * object's superclass, which is Object. The result is | ||
| 172 | * this PermissionCollection's type name followed by this object's | ||
| 173 | * hashcode, thus enabling clients to differentiate different | ||
| 174 | * PermissionCollections object, even if they contain the same permissions. | ||
| 175 | * | ||
| 176 | * @return information about this PermissionCollection object, | ||
| 177 | * as described above. | ||
| 178 | * | ||
| 179 | */ | ||
| 180 | public String toString() { | ||
| 181 | Enumeration<Permission> enum_ = elements(); | ||
| 182 | StringBuilder sb = new StringBuilder(); | ||
| 183 | sb.append(super.toString()+" (\n"); | ||
| 184 | while (enum_.hasMoreElements()) { | ||
| 185 | try { | ||
| 186 | sb.append(" "); | ||
| 187 | sb.append(enum_.nextElement().toString()); | ||
| 188 | sb.append("\n"); | ||
| 189 | } catch (NoSuchElementException e){ | ||
| 190 | // ignore | ||
| 191 | } | ||
| 192 | } | ||
| 193 | sb.append(")\n"); | ||
| 194 | return sb.toString(); | ||
| 195 | } | ||
| 196 | } | ||