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| 1 | +/* | |
| 2 | + * Copyright (c) 1997, 2004, 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 | +/** | |
| 29 | + * A GuardedObject is an object that is used to protect access to | |
| 30 | + * another object. | |
| 31 | + * | |
| 32 | + * <p>A GuardedObject encapsulates a target object and a Guard object, | |
| 33 | + * such that access to the target object is possible | |
| 34 | + * only if the Guard object allows it. | |
| 35 | + * Once an object is encapsulated by a GuardedObject, | |
| 36 | + * access to that object is controlled by the <code>getObject</code> | |
| 37 | + * method, which invokes the | |
| 38 | + * <code>checkGuard</code> method on the Guard object that is | |
| 39 | + * guarding access. If access is not allowed, | |
| 40 | + * an exception is thrown. | |
| 41 | + * | |
| 42 | + * @see Guard | |
| 43 | + * @see Permission | |
| 44 | + * | |
| 45 | + * @author Roland Schemers | |
| 46 | + * @author Li Gong | |
| 47 | + */ | |
| 48 | + | |
| 49 | +public class GuardedObject implements java.io.Serializable { | |
| 50 | + | |
| 51 | + private static final long serialVersionUID = -5240450096227834308L; | |
| 52 | + | |
| 53 | + private Object object; // the object we are guarding | |
| 54 | + private Guard guard; // the guard | |
| 55 | + | |
| 56 | + /** | |
| 57 | + * Constructs a GuardedObject using the specified object and guard. | |
| 58 | + * If the Guard object is null, then no restrictions will | |
| 59 | + * be placed on who can access the object. | |
| 60 | + * | |
| 61 | + * @param object the object to be guarded. | |
| 62 | + * | |
| 63 | + * @param guard the Guard object that guards access to the object. | |
| 64 | + */ | |
| 65 | + | |
| 66 | + public GuardedObject(Object object, Guard guard) | |
| 67 | + { | |
| 68 | + this.guard = guard; | |
| 69 | + this.object = object; | |
| 70 | + } | |
| 71 | + | |
| 72 | + /** | |
| 73 | + * Retrieves the guarded object, or throws an exception if access | |
| 74 | + * to the guarded object is denied by the guard. | |
| 75 | + * | |
| 76 | + * @return the guarded object. | |
| 77 | + * | |
| 78 | + * @exception SecurityException if access to the guarded object is | |
| 79 | + * denied. | |
| 80 | + */ | |
| 81 | + public Object getObject() | |
| 82 | + throws SecurityException | |
| 83 | + { | |
| 84 | + if (guard != null) | |
| 85 | + guard.checkGuard(object); | |
| 86 | + | |
| 87 | + return object; | |
| 88 | + } | |
| 89 | + | |
| 90 | + /** | |
| 91 | + * Writes this object out to a stream (i.e., serializes it). | |
| 92 | + * We check the guard if there is one. | |
| 93 | + */ | |
| 94 | + private void writeObject(java.io.ObjectOutputStream oos) | |
| 95 | + throws java.io.IOException | |
| 96 | + { | |
| 97 | + if (guard != null) | |
| 98 | + guard.checkGuard(object); | |
| 99 | + | |
| 100 | + oos.defaultWriteObject(); | |
| 101 | + } | |
| 102 | +} | |