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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 | } | ||