1 /* 2 * Copyright (c) 1997, 2021, 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.io.IOException; 29 30 /** 31 * A GuardedObject is an object that is used to protect access to 32 * another object. 33 * 34 * <p>A GuardedObject encapsulates a target object and a Guard object, 35 * such that access to the target object is possible 36 * only if the Guard object allows it. 37 * Once an object is encapsulated by a GuardedObject, 38 * access to that object is controlled by the {@code getObject} 39 * method, which invokes the 40 * {@code checkGuard} method on the Guard object that is 41 * guarding access. If access is not allowed, 42 * an exception is thrown. 43 * 44 * @see Guard 45 * @see Permission 46 * 47 * @author Roland Schemers 48 * @author Li Gong 49 * @since 1.2 50 */ 51 52 public class GuardedObject implements java.io.Serializable { 53 54 @java.io.Serial 55 private static final long serialVersionUID = -5240450096227834308L; 56 57 /** 58 * The object we are guarding. 59 */ 60 @SuppressWarnings("serial") // Not statically typed as Serializable 61 private Object object; 62 63 /** 64 * The guard object. 65 */ 66 @SuppressWarnings("serial") // Not statically typed as Serializable 67 private Guard guard; 68 69 /** 70 * Constructs a GuardedObject using the specified object and guard. 71 * If the Guard object is null, then no restrictions will 72 * be placed on who can access the object. 73 * 74 * @param object the object to be guarded. 75 * 76 * @param guard the Guard object that guards access to the object. 77 */ 78 GuardedObject(Object object, Guard guard)79 public GuardedObject(Object object, Guard guard) 80 { 81 this.guard = guard; 82 this.object = object; 83 } 84 85 /** 86 * Retrieves the guarded object, or throws an exception if access 87 * to the guarded object is denied by the guard. 88 * 89 * @return the guarded object. 90 * 91 * @throws SecurityException if access to the guarded object is 92 * denied. 93 */ getObject()94 public Object getObject() 95 throws SecurityException 96 { 97 if (guard != null) 98 guard.checkGuard(object); 99 100 return object; 101 } 102 103 /** 104 * Writes this object out to a stream (i.e., serializes it). 105 * We check the guard if there is one. 106 * 107 * @param oos the {@code ObjectOutputStream} to which data is written 108 * @throws IOException if an I/O error occurs 109 */ 110 @java.io.Serial writeObject(java.io.ObjectOutputStream oos)111 private void writeObject(java.io.ObjectOutputStream oos) 112 throws IOException 113 { 114 if (guard != null) 115 guard.checkGuard(object); 116 117 oos.defaultWriteObject(); 118 } 119 } 120