001    /* Group.java -- Represents a group of Principals
002       Copyright (C) 1998, 2001 Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010    
011    GNU Classpath is distributed in the hope that it will be useful, but
012    WITHOUT ANY WARRANTY; without even the implied warranty of
013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
028    executable, regardless of the license terms of these independent
029    modules, and to copy and distribute the resulting executable under
030    terms of your choice, provided that you also meet, for each linked
031    independent module, the terms and conditions of the license of that
032    module.  An independent module is a module which is not derived from
033    or based on this library.  If you modify this library, you may extend
034    this exception to your version of the library, but you are not
035    obligated to do so.  If you do not wish to do so, delete this
036    exception statement from your version. */
037    
038    package java.security.acl;
039    
040    import java.security.Principal;
041    import java.util.Enumeration;
042    
043    /**
044     * This interface represents a group of <code>Principals</code>.  Note that
045     * since this interface extends <code>Principal</code>, a <code>Group</code>
046     * can be used where ever a <code>Principal</code> is requested.  This
047     * includes arguments to the methods in this interface.
048     *
049     * @version 0.0
050     *
051     * @author Aaron M. Renn (arenn@urbanophile.com)
052     */
053    public interface Group extends Principal
054    {
055      /**
056       * This method adds a new <code>Principal</code> to this group.
057       *
058       * @param user The new <code>Principal</code> to add
059       *
060       * @return <code>true</code> if the user was successfully added or <code>false</code> if the user is already a member
061       */
062      boolean addMember(Principal user);
063    
064      /**
065       * This method deletes a member from the group.
066       *
067       * @param user The <code>Principal</code> to delete
068       *
069       * @return <code>true</code> if the user was successfully deleted or <code>false</code> if the user is not a member of the group
070       */
071      boolean removeMember(Principal user);
072    
073      /**
074       * This method tests whether or not a given <code>Principal</code> is a
075       * member of this group.
076       *
077       * @param member The <code>Principal</code> to test for membership
078       *
079       * @return <code>true</code> if the user is member, <code>false</code> otherwise
080       */
081      boolean isMember(Principal member);
082    
083      /**
084       * This method returns a list of all members of the group as an
085       * <code>Enumeration</code>.
086       *
087       * @return The list of all members of the group
088       */
089      Enumeration<? extends Principal> members();
090    }