1 /* 2 * Copyright (c) 1996, 2013, 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 java.security.acl; 27 28 import java.util.Enumeration; 29 import java.security.Principal; 30 31 /** 32 * This is the interface used for representing one entry in an Access 33 * Control List (ACL).<p> 34 * 35 * An ACL can be thought of as a data structure with multiple ACL entry 36 * objects. Each ACL entry object contains a set of permissions associated 37 * with a particular principal. (A principal represents an entity such as 38 * an individual user or a group). Additionally, each ACL entry is specified 39 * as being either positive or negative. If positive, the permissions are 40 * to be granted to the associated principal. If negative, the permissions 41 * are to be denied. Each principal can have at most one positive ACL entry 42 * and one negative entry; that is, multiple positive or negative ACL 43 * entries are not allowed for any principal. 44 * 45 * Note: ACL entries are by default positive. An entry becomes a 46 * negative entry only if the 47 * {@link #setNegativePermissions() setNegativePermissions} 48 * method is called on it. 49 * 50 * @see java.security.acl.Acl 51 * 52 * @author Satish Dharmaraj 53 */ 54 public interface AclEntry extends Cloneable { 55 56 /** 57 * Specifies the principal for which permissions are granted or denied 58 * by this ACL entry. If a principal was already set for this ACL entry, 59 * false is returned, otherwise true is returned. 60 * 61 * @param user the principal to be set for this entry. 62 * 63 * @return true if the principal is set, false if there was 64 * already a principal set for this entry. 65 * 66 * @see #getPrincipal 67 */ setPrincipal(Principal user)68 public boolean setPrincipal(Principal user); 69 70 /** 71 * Returns the principal for which permissions are granted or denied by 72 * this ACL entry. Returns null if there is no principal set for this 73 * entry yet. 74 * 75 * @return the principal associated with this entry. 76 * 77 * @see #setPrincipal 78 */ getPrincipal()79 public Principal getPrincipal(); 80 81 /** 82 * Sets this ACL entry to be a negative one. That is, the associated 83 * principal (e.g., a user or a group) will be denied the permission set 84 * specified in the entry. 85 * 86 * Note: ACL entries are by default positive. An entry becomes a 87 * negative entry only if this {@code setNegativePermissions} 88 * method is called on it. 89 */ setNegativePermissions()90 public void setNegativePermissions(); 91 92 /** 93 * Returns true if this is a negative ACL entry (one denying the 94 * associated principal the set of permissions in the entry), false 95 * otherwise. 96 * 97 * @return true if this is a negative ACL entry, false if it's not. 98 */ isNegative()99 public boolean isNegative(); 100 101 /** 102 * Adds the specified permission to this ACL entry. Note: An entry can 103 * have multiple permissions. 104 * 105 * @param permission the permission to be associated with 106 * the principal in this entry. 107 * 108 * @return true if the permission was added, false if the 109 * permission was already part of this entry's permission set. 110 */ addPermission(Permission permission)111 public boolean addPermission(Permission permission); 112 113 /** 114 * Removes the specified permission from this ACL entry. 115 * 116 * @param permission the permission to be removed from this entry. 117 * 118 * @return true if the permission is removed, false if the 119 * permission was not part of this entry's permission set. 120 */ removePermission(Permission permission)121 public boolean removePermission(Permission permission); 122 123 /** 124 * Checks if the specified permission is part of the 125 * permission set in this entry. 126 * 127 * @param permission the permission to be checked for. 128 * 129 * @return true if the permission is part of the 130 * permission set in this entry, false otherwise. 131 */ checkPermission(Permission permission)132 public boolean checkPermission(Permission permission); 133 134 /** 135 * Returns an enumeration of the permissions in this ACL entry. 136 * 137 * @return an enumeration of the permissions in this ACL entry. 138 */ permissions()139 public Enumeration<Permission> permissions(); 140 141 /** 142 * Returns a string representation of the contents of this ACL entry. 143 * 144 * @return a string representation of the contents. 145 */ toString()146 public String toString(); 147 148 /** 149 * Clones this ACL entry. 150 * 151 * @return a clone of this ACL entry. 152 */ clone()153 public Object clone(); 154 } 155