001/* Owner.java -- ACL owner
002   Copyright (C) 1998 Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038package java.security.acl;
039
040import java.security.Principal;
041
042/**
043 * This interface provides a mechanism for maintaining a list of owners
044 * of an access control list (ACL).  Since a <code>Principal</code> must
045 * be an owner in order to modify the owner list, a mechanism must be
046 * provided to specify the initial owner of the ACL.  The proper way to do
047 * this is for the implementing class to specify the initial owner in
048 * the contructor for that class.
049 *
050 * @version 0.0
051 *
052 * @author Aaron M. Renn (arenn@urbanophile.com)
053 */
054public interface Owner
055{
056  /**
057   * This method adds an owner to the access control list (ACL).  Only a
058   * <code>Principal</code> who is already an owner can perform this operation.
059   *
060   * @param caller The <code>Principal</code> who is requesting that an owner be added
061   * @param owner The <code>Principal</code> to add as a new owner
062   *
063   * @param <code>true</code> if the new owner was successfully added or <code>false</code> if the specified new owner is already an owner
064   *
065   * @exception NotOwnerException If the caller is not already an owner of this ACL
066   */
067  boolean addOwner(Principal caller, Principal owner) 
068    throws NotOwnerException;
069
070  /**
071   * This method delets an owner from the access control list (ACL).  Only a
072   * <code>Principal</code> who is an owner can perform this operation.  An
073   * owner can delete itself from the list.  If there is only one
074   * owner remaining on this list, any attempt to delete it will throw an
075   * exception.
076   *
077   * @param caller The <code>Principal</code> who is requesting that an owner be deleted
078   * @param owner The <code>Principal</code> to delete as an owner
079   *
080   * @param <code>true</code> if the new owner was successfully deleted or <code>false</code> if the specified owner is not currently an owner
081   *
082   * @exception NotOwnerException If the caller is not already an owner of this ACL
083   * @exception LastOwnerException If completing the operation would delete the last ACL owner
084   */
085  boolean deleteOwner(Principal caller, Principal owner) 
086    throws NotOwnerException, LastOwnerException;
087
088  /**
089   * This method tests whether or not a given <code>Principal</code> is an
090   * owner of this access control list (ACL).
091   *
092   * @return <code>true</code> if the <code>Principal</code> is an owner, <code>false</code> otherwise
093   */
094  boolean isOwner(Principal owner);
095}