1 /*
   2  * Copyright (c) 1999, 2000, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package com.sun.security.auth;
  27 
  28 /**
  29  * An object that implements the <code>java.security.Principal</code>
  30  * interface typically also implements this interface to provide
  31  * a means for comparing that object to a specified <code>Subject</code>.
  32  *
  33  * <p> The comparison is achieved via the <code>implies</code> method.
  34  * The implementation of the <code>implies</code> method determines
  35  * whether this object "implies" the specified <code>Subject</code>.
  36  * One example application of this method may be for
  37  * a "group" object to imply a particular <code>Subject</code>
  38  * if that <code>Subject</code> belongs to the group.
  39  * Another example application of this method would be for
  40  * "role" object to imply a particular <code>Subject</code>
  41  * if that <code>Subject</code> is currently acting in that role.
  42  *
  43  * <p> Although classes that implement this interface typically
  44  * also implement the <code>java.security.Principal</code> interface,
  45  * it is not required.  In other words, classes may implement the
  46  * <code>java.security.Principal</code> interface by itself,
  47  * the <code>PrincipalComparator</code> interface by itself,
  48  * or both at the same time.
  49  *
  50  * @see java.security.Principal
  51  * @see javax.security.auth.Subject
  52  */
  53 @jdk.Supported
  54 public interface PrincipalComparator {
  55     /**
  56      * Check if the specified <code>Subject</code> is implied by
  57      * this object.
  58      *
  59      * <p>
  60      *
  61      * @return true if the specified <code>Subject</code> is implied by
  62      *          this object, or false otherwise.
  63      */
  64     boolean implies(javax.security.auth.Subject subject);
  65 }