libjava/java/security/acl/AclEntry.java

   1 /* AclEntry.java -- An entry in an ACL list.
   2    Copyright (C) 1998 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38 package java.security.acl;
  39
  40 import java.security.Principal;
  41 import java.util.Enumeration;
  42
  43 /**
  44  * This interface models an entry in an access control list (ACL).  Java
  45  * ACL's consist of a list of entries, where each consists of a
  46  * <code>Principal</code> and a list of <code>Permission</code>'s which
  47  * have been granted to that <code>Principal</code>.  An ACL can also
  48  * be <em>negative</em>, which indicates that the list of
  49  * <code>Permission</code>'s is a list of permissions that are <em>not</em>
  50  * granted to the <code>Principal</code>.  A <code>Principal</code> can
  51  * have at most one regular (or positive) ACL entry and one negative
  52  * ACL entry.
  53  *
  54  * @version 0.0
  55  *
  56  * @author Aaron M. Renn (arenn@urbanophile.com)
  57  */
  58 public interface AclEntry extends Cloneable
  59 {
  60  /**
  61    * This method returns the <code>Principal</code> associated with this
  62    * ACL entry.
  63    *
  64    * @return The <code>Principal</code> for this ACL entry
  65    */
  66   Principal getPrincipal();
  67
  68   /**
  69    * This method sets ths <code>Principal</code> associated with this
  70    * ACL entry.  This operation will only succeed if there is not already
  71    * a <code>Principal</code> assigned.
  72    *
  73    * @param user The <code>Principal</code> for this ACL entry
  74    *
  75    * @return <code>true</code> if the <code>Principal</code> was successfully set or <code>false</code> if this entry already has a <code>Principal</code>.
  76    */
  77   boolean setPrincipal(Principal user);
  78
  79   /**
  80    * This method sets this ACL entry to be a <em>negative</em> entry, indicating
  81    * that it contains a list of permissions that are <em>not</em> granted
  82    * to the entry's <code>Principal</code>.  Note that there is no way to
  83    * undo this operation.
  84    */
  85   void setNegativePermissions();
  86
  87   /**
  88    * This method tests whether or not this ACL entry is a negative entry or not.
  89    *
  90    * @return <code>true</code> if this ACL entry is negative, <code>false</code> otherwise
  91    */
  92   boolean isNegative();
  93
  94   /**
  95    * This method adds the specified permission to this ACL entry.
  96    *
  97    * @param perm The <code>Permission</code> to add
  98    *
  99    * @return <code>true</code> if the permission was added or <code>false</code> if it was already set for this entry
 100    */
 101   boolean addPermission(Permission permission);
 102
 103   /**
 104    * This method deletes the specified permission to this ACL entry.
 105    *
 106    * @param perm The <code>Permission</code> to delete from this ACL entry.
 107    *
 108    * @return <code>true</code> if the permission was successfully deleted or <code>false</code> if the permission was not part of this ACL to begin with
 109    */
 110   boolean removePermission(Permission perm);
 111
 112   /**
 113    * This method tests whether or not the specified permission is associated
 114    * with this ACL entry.
 115    *
 116    * @param perm The <code>Permission</code> to test
 117    *
 118    * @return <code>true</code> if this permission is associated with this entry or <code>false</code> otherwise
 119    */
 120   boolean checkPermission(Permission permission);
 121
 122   /**
 123    * This method returns a list of all <code>Permission</code> objects
 124    * associated with this ACL entry as an <code>Enumeration</code>.
 125    *
 126    * @return A list of permissions for this ACL entry
 127    */
 128   Enumeration permissions();
 129
 130   /**
 131    * This method returns this object as a <code>String</code>.
 132    *
 133    * @return A <code>String</code> representation of this object
 134    */
 135   String toString();
 136
 137   /**
 138    * This method returns a clone of this ACL entry
 139    *
 140    * @return A clone of this ACL entry
 141    */
 142   Object clone();
 143 }