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Diffstat (limited to 'libjava/classpath/java/security/GuardedObject.java')
-rw-r--r-- | libjava/classpath/java/security/GuardedObject.java | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/libjava/classpath/java/security/GuardedObject.java b/libjava/classpath/java/security/GuardedObject.java new file mode 100644 index 0000000..5ca0883 --- /dev/null +++ b/libjava/classpath/java/security/GuardedObject.java @@ -0,0 +1,121 @@ +/* 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., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 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 |