1 /*

     2  * Copyright (c) 1996, 2011, 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 sun.security.acl;

    27 

    28 import java.util.*;

    29 import java.security.*;

    30 import java.security.acl.*;

    31 

    32 /**

    33  * This class implements a group of principals.

    34  * @author      Satish Dharmaraj

    35  */

    36 public class GroupImpl implements Group {

    37     private Vector<Principal> groupMembers = new Vector<>(50, 100);

    38     private String group;

    39 

    40     /**

    41      * Constructs a Group object with no members.

    42      * @param groupName the name of the group

    43      */

    44     public GroupImpl(String groupName) {

    45         this.group = groupName;

    46     }

    47 

    48     /**

    49      * adds the specified member to the group.

    50      * @param user The principal to add to the group.

    51      * @return true if the member was added - false if the

    52      * member could not be added.

    53      */

    54     public boolean addMember(Principal user) {

    55         if (groupMembers.contains(user))

    56           return false;

    57 

    58         // do not allow groups to be added to itself.

    59         if (group.equals(user.toString()))

    60             throw new IllegalArgumentException();

    61 

    62         groupMembers.addElement(user);

    63         return true;

    64     }

    65 

    66     /**

    67      * removes the specified member from the group.

    68      * @param user The principal to remove from the group.

    69      * @param true if the principal was removed false if

    70      * the principal was not a member

    71      */

    72     public boolean removeMember(Principal user) {

    73         return groupMembers.removeElement(user);

    74     }

    75 

    76     /**

    77      * returns the enumeration of the members in the group.

    78      */

    79     public Enumeration<? extends Principal> members() {

    80         return groupMembers.elements();

    81     }

    82 

    83     /**

    84      * This function returns true if the group passed matches

    85      * the group represented in this interface.

    86      * @param another The group to compare this group to.

    87      */

    88     public boolean equals(Object obj) {

    89         if (this == obj) {

    90             return true;

    91         }

    92         if (obj instanceof Group == false) {

    93             return false;

    94         }

    95         Group another = (Group)obj;

    96         return group.equals(another.toString());

    97     }

    98 

    99     // equals(Group) for compatibility

   100     public boolean equals(Group another) {

   101         return equals((Object)another);

   102     }

   103 

   104     /**

   105      * Prints a stringified version of the group.

   106      */

   107     public String toString() {

   108         return group;

   109     }

   110 

   111     /**

   112      * return a hashcode for the principal.

   113      */

   114     public int hashCode() {

   115         return group.hashCode();

   116     }

   117 

   118     /**

   119      * returns true if the passed principal is a member of the group.

   120      * @param member The principal whose membership must be checked for.

   121      * @return true if the principal is a member of this group,

   122      * false otherwise

   123      */

   124     public boolean isMember(Principal member) {

   125 

   126         //

   127         // if the member is part of the group (common case), return true.

   128         // if not, recursively search depth first in the group looking for the

   129         // principal.

   130         //

   131         if (groupMembers.contains(member)) {

   132             return true;

   133         } else {

   134             Vector<Group> alreadySeen = new Vector<>(10);

   135             return isMemberRecurse(member, alreadySeen);

   136         }

   137     }

   138 

   139     /**

   140      * return the name of the principal.

   141      */

   142     public String getName() {

   143         return group;

   144     }

   145 

   146     //

   147     // This function is the recursive search of groups for this

   148     // implementation of the Group. The search proceeds building up

   149     // a vector of already seen groups. Only new groups are considered,

   150     // thereby avoiding loops.

   151     //

   152     boolean isMemberRecurse(Principal member, Vector<Group> alreadySeen) {

   153         Enumeration<? extends Principal> e = members();

   154         while (e.hasMoreElements()) {

   155             boolean mem = false;

   156             Principal p = (Principal) e.nextElement();

   157 

   158             // if the member is in this collection, return true

   159             if (p.equals(member)) {

   160                 return true;

   161             } else if (p instanceof GroupImpl) {

   162                 //

   163                 // if not recurse if the group has not been checked already.

   164                 // Can call method in this package only if the object is an

   165                 // instance of this class. Otherwise call the method defined

   166                 // in the interface. (This can lead to a loop if a mixture of

   167                 // implementations form a loop, but we live with this improbable

   168                 // case rather than clutter the interface by forcing the

   169                 // implementation of this method.)

   170                 //

   171                 GroupImpl g = (GroupImpl) p;

   172                 alreadySeen.addElement(this);

   173                 if (!alreadySeen.contains(g))

   174                   mem =  g.isMemberRecurse(member, alreadySeen);

   175             } else if (p instanceof Group) {

   176                 Group g = (Group) p;

   177                 if (!alreadySeen.contains(g))

   178                   mem = g.isMember(member);

   179             }

   180 

   181             if (mem)

   182               return mem;

   183         }

   184         return false;

   185     }

   186 }