001/* AclEntry.java -- An entry in an ACL list. 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; 041import java.util.Enumeration; 042 043/** 044 * This interface models an entry in an access control list (ACL). Java 045 * ACL's consist of a list of entries, where each consists of a 046 * <code>Principal</code> and a list of <code>Permission</code>'s which 047 * have been granted to that <code>Principal</code>. An ACL can also 048 * be <em>negative</em>, which indicates that the list of 049 * <code>Permission</code>'s is a list of permissions that are <em>not</em> 050 * granted to the <code>Principal</code>. A <code>Principal</code> can 051 * have at most one regular (or positive) ACL entry and one negative 052 * ACL entry. 053 * 054 * @version 0.0 055 * 056 * @author Aaron M. Renn (arenn@urbanophile.com) 057 */ 058public interface AclEntry extends Cloneable 059{ 060 /** 061 * This method returns the <code>Principal</code> associated with this 062 * ACL entry. 063 * 064 * @return The <code>Principal</code> for this ACL entry 065 */ 066 Principal getPrincipal(); 067 068 /** 069 * This method sets ths <code>Principal</code> associated with this 070 * ACL entry. This operation will only succeed if there is not already 071 * a <code>Principal</code> assigned. 072 * 073 * @param user The <code>Principal</code> for this ACL entry 074 * 075 * @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>. 076 */ 077 boolean setPrincipal(Principal user); 078 079 /** 080 * This method sets this ACL entry to be a <em>negative</em> entry, indicating 081 * that it contains a list of permissions that are <em>not</em> granted 082 * to the entry's <code>Principal</code>. Note that there is no way to 083 * undo this operation. 084 */ 085 void setNegativePermissions(); 086 087 /** 088 * This method tests whether or not this ACL entry is a negative entry or not. 089 * 090 * @return <code>true</code> if this ACL entry is negative, <code>false</code> otherwise 091 */ 092 boolean isNegative(); 093 094 /** 095 * This method adds the specified permission to this ACL entry. 096 * 097 * @param permission The <code>Permission</code> to add 098 * 099 * @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 permission 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<Permission> 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}