content: /*
   * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
   * particular file as subject to the "Classpath" exception as provided
   * by Oracle in the LICENSE file that accompanied this code.
   *
   * This code 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
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  
  package java.security;
  
  /**
   * A GuardedObject is an object that is used to protect access to
   * another object.
   *
   * <p>A GuardedObject encapsulates a target object and a Guard object,
   * such that access to the target object is possible
   * only if the Guard object allows it.
   * Once an object is encapsulated by a GuardedObject,
   * access to that object is controlled by the {@code getObject}
   * method, which invokes the
   * {@code checkGuard} method on the Guard object that is
   * guarding access. If access is not allowed,
   * an exception is thrown.
   *
   * @see Guard
   * @see Permission
   *
   * @author Roland Schemers
   * @author Li Gong
   */
  
  public class GuardedObject implements java.io.Serializable {
  
      private static final long serialVersionUID = -5240450096227834308L;
  
      private Object object; // the object we are guarding
      private Guard guard;   // the guard
  
      /**
       * Constructs a GuardedObject using the specified object and guard.
       * If the Guard object is null, then no restrictions will
       * be placed on who can access the object.
       *
       * @param object the object to be guarded.
       *
       * @param guard the Guard object that guards access to the object.
       */
  
      public GuardedObject(Object object, Guard guard)
      {
          this.guard = guard;
          this.object = object;
      }
  
      /**
       * Retrieves the guarded object, or throws an exception if access
       * to the guarded object is denied by the guard.
       *
       * @return the guarded object.
       *
       * @exception SecurityException if access to the guarded object is
       * denied.
       */
      public Object getObject()
          throws SecurityException
      {
          if (guard != null)
              guard.checkGuard(object);
  
          return object;
      }
  
      /**
       * Writes this object out to a stream (i.e., serializes it).
       * We check the guard if there is one.
       */
      private void writeObject(java.io.ObjectOutputStream oos)
          throws java.io.IOException
      {
          if (guard != null)
              guard.checkGuard(object);
  
          oos.defaultWriteObject();
      }
  }
  