| /* GuardedObject.java -- An object protected by a Guard |
| Copyright (C) 1998, 2002, 2004, 2005 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package java.security; |
| |
| import java.io.IOException; |
| import java.io.ObjectOutputStream; |
| import java.io.Serializable; |
| |
| /** |
| * This class is an object that is guarded by a <code>Guard</code> object. |
| * The object that is being guarded is retrieved by a call to the only |
| * method in this class - <code>getObject</code>. That method returns the |
| * guarded <code>Object</code> after first checking with the |
| * <code>Guard</code>. If the <code>Guard</code> disallows access, an |
| * exception will be thrown. |
| * |
| * @author Aaron M. Renn (arenn@urbanophile.com) |
| * @since 1.1 |
| * @status updated to 1.4 |
| */ |
| public class GuardedObject implements Serializable |
| { |
| /** |
| * Compatible with JDK 1.1+. |
| */ |
| private static final long serialVersionUID = -5240450096227834308L; |
| |
| /** |
| * This is the Guard that is protecting the object. |
| * |
| * @serial the guard |
| */ |
| private final Guard guard; |
| |
| /** |
| * This is the object that is being guarded. |
| * |
| * @serial the protected object |
| */ |
| private final Object object; |
| |
| /** |
| * This method initializes a new instance of <code>GuardedObject</code> |
| * that protects the specified <code>Object</code> using the specified |
| * <code>Guard</code>. A null guard means there are no restrictions on |
| * accessing the object. |
| * |
| * @param object the <code>Object</code> to guard |
| * @param guard the <code>Guard</code> that is protecting the object |
| */ |
| public GuardedObject(Object object, Guard guard) |
| { |
| this.object = object; |
| this.guard = guard; |
| } |
| |
| /** |
| * This method first call the <code>checkGuard</code> method on the |
| * <code>Guard</code> object protecting the guarded object. If the |
| * <code>Guard</code> disallows access, an exception is thrown, otherwise |
| * the <code>Object</code> is returned. |
| * |
| * @return The object being guarded |
| * @throws SecurityException if access is denied |
| */ |
| public Object getObject() |
| { |
| if (guard != null) |
| guard.checkGuard(object); |
| return object; |
| } |
| |
| /** |
| * Ensures that serialization is legal, by checking the guard. |
| * |
| * @param s the stream to write to |
| * @throws IOException if the underlying stream fails |
| */ |
| private void writeObject(ObjectOutputStream s) throws IOException |
| { |
| if (guard != null) |
| guard.checkGuard(object); |
| s.defaultWriteObject(); |
| } |
| } // class GuardedObject |